what is iris diaphragm

Answers

Answer 1

Answer:

noun Optics, Photography. a composite diaphragm with a central aperture readily adjustable for size, used to regulate the amount of light admitted to a lens or optical system. Also called iris.

Explanation:

Answer 2
a flat, colored, ring-shaped membrane behind the cornea of the eye, with an adjustable circular opening (pupil) in the center.
Thanks!

Related Questions

How many calories are found in food that is labeled 20 Calories?

Answers

Answer:

20 Calories

Explanation:

If a food product is labeled to contain 20 calories, it likely contains the number of calories. Keep in mind, these labels can be inaccurate.

I will give brainlist

In animal cells, cytokinesis is accomplished by using cell plate.



true

false

Answers

Answer:

true

i hope its help

carry on learning

In animal cells, cytokinesis is accomplished by using cell plate.

TRUE

False

Answer:

True

state the different types of enzyme inhabitors

Answers

Answer:

Reversible and irreversible inhibitors are chemicals which bind to an enzyme to suppress its activity.

The important types of inhibitors are competitive, noncompetitive, and uncompetitive inhibitors.

Explanation:

BY Roses_are_Rosie

1. Alpha-gamma coactivation
A. is critical for preventing contraction of an antagonist muscle when the other muscle is contracting during voluntary
movement
B. is critical for maintaining the appropriate tension on the spindle organ during contraction of extrafusal fibers.
C. is the process by which Ca2+ is released from the sarcolemma when nicotinic acetylcholine receptors are activated
at the neuromuscular junction
none of the above

Answers

The correct option is B.

Alpha gamma coactivation is critical for maintaining the appropriate tension on the spindle organ during contraction of extrafusal fiber.

Alpha‐gamma coactivation is a process that the muscle use to keep or maintains it's length. It works in a way that when the muscle contracts or relaxes , the sensory neuron send the information to the central nervous system about what happen to the muscle. This lead the intrafusal and extrafusal fibers to contract.

Alpha-gamma coactivation enhance the muscle spindles ensure its sensitivity to stretch the muscle lengths.

Therefore, Alpha gamma coactivation is critical for maintaining the appropriate tension on the spindle organ during contraction of extrafusal fiber.

For further details check the following link.

https://brainly.com/question/9011834

Explain what happens in each stage of mitosis.
no links

Answers

Answer:

Stage #1 Prophase: Chromatin fibers become coiled into chromosomes, with each chromosome having two chromatids joined at a centromere.

The mitotic spindle, composed of microtubules and proteins, forms in the cytoplasm.

The two pairs of centrioles (formed from the replication of one pair in Interphase) move away from one another toward opposite ends of the cell due to the lengthening of the ​microtubules that form between them.

Polar fibers, which are microtubules that make up the spindle fibers, reach from each cell pole to the cell's equator.

Kinetochores, which are specialized regions in the centromeres of chromosomes, attach to a type of microtubule called kinetochore fibers.

The kinetochore fibers "interact" with the spindle polar fibers connecting the kinetochores to the polar fibers.

The chromosomes begin to migrate toward the cell center.

Stage #2 Metaphase: The nuclear membrane disappears completely.

Polar fibers (microtubules that make up the spindle fibers) continue to extend from the poles to the center of the cell.

Chromosomes move randomly until they attach (at their kinetochores) to polar fibers from both sides of their centromeres.

Chromosomes align at the metaphase plate at right angles to the spindle poles.

Chromosomes are held at the metaphase plate by the equal forces of the polar fibers pushing on the centromeres of the chromosomes.

Stage #3: Anaphase: The paired centromeres in each distinct chromosome begin to move apart.​

Once the paired sister chromatids separate from one another, each is considered a "full" chromosome. They are referred to as daughter chromosomes.​

Through the spindle apparatus, the daughter chromosomes move to the poles at opposite ends of the cell.​

The daughter chromosomes migrate centromere first and the kinetochore fibers become shorter as the chromosomes near a pole.​

In preparation for telophase, the two cell poles also move further apart during the course of anaphase. At the end of anaphase, each pole contains a complete compilation of chromosomes.

Stage #4 Telophase: The polar fibers continue to lengthen.

Nuclei begin to form at opposite poles.

The nuclear envelopes of these nuclei form from remnant pieces of the parent cell's nuclear envelope and from pieces of the endomembrane system.

Nucleoli also reappear.

Chromatin fibers of chromosomes uncoil.

After these changes, telophase/mitosis is largely complete. The genetic contents of one cell have been divided equally into two.

Stage #5 Cytokinesis: Cytokinesis is the division of the cell's cytoplasm. It begins prior to the end of mitosis in anaphase and completes shortly after telophase/mitosis. At the end of cytokinesis, two genetically identical daughter cells are produced. These are diploid cells, with each cell containing a full complement of chromosomes.

Cells produced through mitosis are different from those produced through meiosis. In meiosis, four daughter cells are produced. These cells are haploid cells, containing one-half the number of chromosomes as the original cell. Sex cells undergo meiosis. When sex cells unite during fertilization, these haploid cells become a diploid cell.​

Explanation:

can you please help?​

Answers

Answer:

it's b

hope it will help you

How do endocrine glands send messages to other organs?

Answers

Answer:

Endocrine glands make chemicals called hormones and pass them straight into the bloodstream. Hormones can be thought of as chemical messages. From the blood stream, the hormones communicate with the body by heading towards their target cell to bring about a particular change or effect to that cell

When someone is infected with cholera, the cholera toxin acts as a

A. ligand
B. receptor
C. cellular response
D. nucleus

Answers

Answer:

I think it acts as a receptor

B. Receptor ok ok ok ok ok ok

The answers are


A: Cholesterol


B:

Integral protein


C: Glycolipid


D: Glycoprotein

Answers

Answer:

sis /  bro

whats the question pls type in the comment of mine and i will say the answer

Precipitation moving from higher to lower elevations on the ground is called___?

Answers

Answer:

Evaporation

Explanation:

Evaporation is the process in which percipitation moves higher to lower elavations on the ground. Evaporation is when the sun heats up and dries out the water causing it to rise up to the clouds which then causes rain for another time. ( I am not completely sure)

which involves transport proteins?
A. Osmosis
B. Diffusion
C. Active transport
D. Passive Transport ​

Answers

Answer:

C

Explanation:

Which method of timber harvesting removes all trees from the harvest area?

Answers

Clear-cutting is the most common method of timber removal. Clear-cutting removes all the trees in a given area, often by using large machinery. From an economic standpoint, the benefit of this approach is that humans can harvest maximum timber with minimal energy and cost.

When did Lincoln declare that Thanksgiving would be celebrated on the last Thursday of November?

Answers

(1863). Lincoln declared that Thanksgiving would be celebrated in 1863!

An island experiences a decade long drought which causes a die off of several plant species. The only plants that survive have extremely small seeds with less nutritional value. Parrots which live on the island and eat seeds are more likely to survive and successfully reproduce if they are smaller since smaller body size requires less calories. Over the course of the decade, the average body size of the parrot population decreases. Which of the following statements below are correct?

a. The parrot population has evolved.
b. This is an example of genetic drift.
c. This is an example of directional selection.
d. This population meets the conditions for the Hardy Weinberg equilibrium.
e. This is an example of stabilizing selection.
f. This is an example of natural selection.

Answers

Answer:

A and f

Explanation:

calculate the magnification of the drawing below, If the length of the leaf is 30mm and the length of the drawing made was 100mm​

Answers

Answer:

10

Explanation:

The magnification of the drawing made was 10 because it had a length of 100mm and originally had a length of 30mm. It can also be said that the magnification is 3 since dividing by the original length (30) we get: 100/30 = 3.

explain four example of cybercrime​

Answers

Answer: Hacking.

XSS: Cross-Site Scripting.

Denial-of-Service Attack.

Phishing Scam.

Spamming.

Explanation:

why do biomes differ

Answers

Answer:

Biomes differ in the amount of precipitation they receive, their temperatures, and the life that inhabits each biome.

Explanation:

Biomes differ in the amount of precipitation they receive, their temperatures, and the life that inhabits each biome.

For example, the types of organisms found in the subtropical desert differ drastically from the organisms found in a tropical rainforest. Each organism is well-adapted to its environment, and a subtropical desert and tropical rainforest are two very different biomes.

If you look at the graph below, you can see that the tropical rainforest has high average temperatures and high precipitation, whereas subtropical deserts have much lower precipitation and great variation in average temperature.

Explanation:


For hypertrophy to occur in skeletal muscle fibers, which subcellular changes must be seen in a muscle cell?

Answers

Answer: at here is selective hypertrophy of type 1 fibers

I think is has something to do with enhancing the strength within the muscle by increasing the number of contractile myofibrils

explain the bone structure

Answers

Answer:

Bones are organs composed of hard living tissue providing structural support to the body – it's scaffolding. It is a hard matrix of calcium salts deposited around protein fibers. Minerals make bone rigid and proteins (collagen) provide strength and elasticity. ... The outer layer of bone is called Cortical bone.

What aspect of a muscle cell
allows movement in the body?
A. its shape is short and blunt
B. fibers within the cell move back and forth
allowing the cell to stretch and shrink
C. there are no organelles which allows it to
move easier

Answers

Answer:

B

Explanation:

Nearly all movement in the body is the result of muscle contraction.

What is eutrophication ?​

Answers

Eutrophication is the process by which an entire body of water, or parts of it, becomes progressively enriched with minerals and nutrients. It has also been defined as "nutrient-induced increase in phytoplankton productivity".

Answer:

excessive richness of nutrients in a lake or other body of water, frequently due to runoff from the land, which causes a dense growth of plant life and death of animal life from lack of oxygen.

Explanation:

Hope it help

7.A frail elderly woman’s body was found in her apartment on a hot summer evening. Her body exhibited advanced rigor in all places except her face and neck

Answers

Answer:

what is the question being asked

Explanation:

Answer:

12-15 hours

Explanation:

All cells in the body have the same genome, with a couple of exceptions. What are these exceptions?

Answers

Answer:

red blood cells, which contain no DNA in their mature state, and some immune system cells that rearrange their DNA while producing antibodies

Cell is the basic unit of life and they contain the needed information known as the DNA (genetic material) to carry out the basic life functions and processes.

All cells in the body essentially have the same genome except some red blood cells and some immune cells.

Red blood cells do not contain as DNA as they lack a nucleus so they are an exception to the rule. While some immune cells needs to reassemble their genome in order to aid in the production of antibodies.

Actually, gene expression comes in with this because cells become different as a result of the fact that a cell can decide which gene is to be expressed or not in accordance to its function it is supposed to perform.

Learn more: https://brainly.com/question/25716827

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Answers

Answer:

kbaf seifhiwksfi kjwas fuesb

Explanation:

iuk ashefuoaeygsh foilkagsbuxvj iskhfewpios ie hiaedghbuad gbv .yes.

Question 1: DNA remains in the nucleus. mRNA can travel in and out of the nucleus. Explain how the function of DNA and mRNA differs. ( Will Mark Brainliest and please only answer if your company 100% sure. And Do Not Repost Someone Else's Answer that is on Brainly Or Any Other Websites Please.​

Answers

Answer:

DNA is a nucleic acid that carries the genetic instructions but mRNA carries information from the DNA to the cytoplasm where proteins are made


The brain is made of what three parts?

A. cerebellum, vertebrae, spinal cord
B. cerebrum, brain stem, skull

C. cerebrum, cerebellum, brain stem

D. cerebellum, brain stem, spinal cord

Answers

Answer:

C. cerebrum, cerebellum, brain stem

Explanation:

The cerebrum is the front part of the brain . it is the largest part of the brain.

cerebellum is the major structure of the brain. cerebellum consists of  cortex covering white matterand a  ventricle filled with fluid.

brainstem connects the cerebrum with the spinal cord.

Answer: C

Explanation: just trust me bro

Examine the model here showing the Milky Way galaxy. Which statements are accurate regarding the galaxy? Select all THREE that
apply.

Answers

Answer:

lame answer

Explanation:

Hey, I need help with these questions please:

Answers

Answer:

10x bigger than bacterial and archaeal cells

A single bout of resistance exercise training increases muscle protein synthesis by as much as ______% above resting levels

Answers

Answer:

A single bout of resistance exercise training increases muscle protein synthesis by as much as 120-150% above resting levels

Explain the effect that temperature has on enzyme activity

Answers

Higher temperatures create more kinetic energy causing enzymes to work faster hence increasing rate of reaction . However if optimum temperature of enzyme is exceeded, enzyme will denature. If temperature is too low, their will be less kinetic energy causing enzymes to work slower and therefore decreasing rate of reaction
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