Biology High School

Why is chalk used on blackboards?

Answers

Answer 1
A blackboard, also called a chalkboard, is a surface on which markings made with chalk are visible. Whiteboards are used because some people are allergic to the dust the chalk used to write on chalkboards generate, and because the dust is hard to clean up when spilled.

Related Questions

3. In a field of sugar beets in Georgia the net primary productivity is 120 grams/m^2/day, and the
respiration loss is 25%. The insolation energy is 800 calories/cm^2/day, and one gram of beets is
equivalent to 2,000 calories.
a. Find the gross productivity of the sugar beets.
b. Using the NPP, calculate the efficiency of photosynthesis for the sugar beets.

Answers

Answer and Explanation:

Available Data:

1 gr beets = 2,000 cal NPP = GPP – Respiration = 120 grams/m2/day NPP= Net primary productivity of a system GPP= Gross productivity of the producers Respiration loss 25% of NPP Insolation energy is 800 calories/cm2/day % Efficiency of Photosynthesis = (NPP/Insolation Energy) X 100

1) Find the gross productivity of the sugar beets.

We need to calculate the GPP, which equals NPP - Respiration rate. The respiration loss is 25% of the NPP. This is:

100% NPP--------------- 120 g/m²/day

25% NPP ----------------X = (25 x 120)/100 = 30 g/m²/day

Now that we know the values of NPP and respiration rate, we can calculate the GPP.

GPP = NPP - Respiration

GPP = 120 (g/m²/day) - 30 (g/m²/day)

GPP = 90 g/m²/day

GPP = 0.009 g/cm²/day

2) Using the NPP, calculate the efficiency of photosynthesis for the sugar beets.

% Efficiency of Photosynthesis = (NPP/Insolation Energy) X 100

We know the NPP, but this value is calculated in g/m²/day, while the Insolation energy is in g/cm²/day. We need to calculate the % Efficiency of Photosynthesis in cm. To do that, we must transform the information.

So if 1 m² = 10,000 cm², then:

10,000cm²----------120 grams/m²/day NPP

1 cm²---------------- (1 x 120) / 10,000 = 0.012 grams/cm²/day NPP

We also know that 1 gr beets = 2,000 cal, and that the Insolation energy is 800 calories/cm²/day

So we need to transform Insolation energy from calories/cm²/day to grams/cm²/day, so:

2,000 calories ----------------- 1 gr beet

800 calories/cm²/day---------X = 0.4 gr beet.

% Efficiency of Photosynthesis = (NPP/Insolation Energy) X 100

% Efficiency of Photosynthesis = (0.012 (gr/cm2/day) /0.4 (gr/cm2/day)) X 100

% Efficiency of Photosynthesis = 3 gr/cm2/day  

which levels of protein structure are expected to be altered as a result of the amino acid substitutions?
1. primary structure
2. secondary structure
3. tertiary structure
4. quaternary structure​

Answers

Answer:

secondary structure

Explanation:

primary structure

Question 1
Which structure is outside the nucleus of a cell and contains
DNA?
A
chromosome
mitochondrion
B
gene
D
vacuole

Answers

Answer:Chromosome

Explanation:

Mitochondria are basically power generators, thats it.

Vacuole acts as a sewage system, dumping excess water and material.

A chromosome is something that makes up a gene, so that cant possibly be right.

Answer:

mitochondrion

Explanation:

The mitochondrion contains mitochondrial DNA which goes back to the  endosymbiotic theory  if you remember that.

15. Preservation focuses mainly on preserving resources so that they can be used by people a. True b. False​

Answers

Answer:

b. False​

Explanation:

Preservation stands for preserving or sustaining what already exists.  aimed at preserving natural resources in their original environment, free from human interference. It stands for securing an object from harm or decay while preserving its nature or state at the same time. Preservation of natural resources does not only benefit humans but also rejuvenates the wildlife and thus gave time for the Earth to breathe and regain its natural form.

About _____ of people develop a serious condition in their phenotype as well as their genotype.

Answers

Answer:

the answer is 8%

3
A scientist mixes 2 grams of water and 6 grams of a powder. A new colored liquid is formed.
How many grams of the new colored liquid result?
(A)
(B)
2 grams
4 grams
6 grams
(C)
(D)
8 grams

Answers

Answer: 8 grams

Explanation: 2 grams of water added with 6 grams of powder equals 8 grams.

i dont know what to in this question

Answers

Answer:

they said to think visually

Explanation:

I hope this helps

Select all that apply. Which of the following are characteristics of eukaryotes? single- or multi-celled structure no distinct nucleus membrane-bound organelles cell(s) larger than prokaryotes

Answers

Answer:

They can be single or multicellular and they are bigger than prokaryotes. They have a distinct nucleus and membrane-bound organelles, so that option would be incorrect. I hope this helped.

Explanation:

Other Questions
3. In a field of sugar beets in Georgia the net primary productivity is 120 grams/m^2/day, and therespiration loss is 25%. The insolation energy is 800 calories/cm^2/day, and one gram of beets isequivalent to 2,000 calories.a. Find the gross productivity of the sugar beets.b. Using the NPP, calculate the efficiency of photosynthesis for the sugar beets. The final step of the decision-making model is: A-describe the situation B-weigh the pros and cons C-take action D-review your decision -36=9a-63 slove for a What is an economy? 1. Benito embroiders and sells T-shirts. The graphshows his profit as a function of the numberof shirts sold. After selling a certain number ofshirts, Benito uses some earnings to buy morematerials and then increases the price of theshirts. Which of the following is true?A )Benito increases the price after selling 50 shirts.B)The y-intercept represents the cost of oneT-shirt.C)The x-intercept represents the shirts he has to sell before making a profit.D)The domain of the function is {x|x is a real number greater than or equal to 0). song about scientific method How many subsets does the set A= {1, 2 3, 4} have? *2 points816412 A music company sells CDs for a particular artist. The company has advertising cost of $4,000 and recoding costs of $10,000; Their cost for manufacturing, royalties, and distribution are $5.50 per CD. They sell the CDs to Mage-Mart for $7.20 each Which statement describes instances of harassment rather than bullying?O Kaylee is teased because she is the smallest person in her class.O Alys is often excluded because she is a lesbian.O Connor is often shoved on the playground by older children.O Hanna is often gossiped about by a group of girls in her class. HELP PLEASE ASYMPTOTES Ron is playing a board game. His game piece is currently on space number 11 on the board. When Ron takes his turn he draws a care that instructs him to move backward 7 spaces. On his following turn he draws a card that instructs him to move forward 7 spaces. Where is Rona piece on the board after his turn? The Sepoy Mutiny in India is MOST similar to which event in China?O A. Taiping RebellionOB.Revolution of 1911O C.establishment of the Manchu DynastyODBoxer Rebellion Who founded the colony of Maryland?Oliver CromwellDuke of YorkCecilius CalvertWilliam Penn Help All atoms of the same element have the same How is a scientific theory different from a scientific law? Which of the following is NOT an example of how the Southwest Indians are using traditional skills to make money? A. raising sheep B. making jewelry C. weaving rugs D. running casinos The controlling idea Question 4 options: Is the thread that weaves through your entire essay. Is supported by your reason statements. Both A & B I need help with all of them but 13B you can answer all of them some of them or just one of them make sure to verify which one you are solving please and thank you Two angles form a linear pair. The measure of one angle is twice the measure of the other angle. Find the measure of each angle.The smaller angle measuresThe larger angle measures Find the coordinates for the vertex of the graph of the function y = 3x 12x+12.A (-2, 48)B. (0, 2)C. (-2, 0)D. (2,0)