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ch4aika [34]
3 years ago
13

A student observers melting crayons. Which of the following describes what they saw? A. A chemical change. B. A physical change.

C. A physical property. D. A chemical property
Biology
1 answer:
tatyana61 [14]3 years ago
8 0

Answer: A physical change

Explanation: since the melted they are still Crayons. You can freeze it and it would still be a crayon. So it was only a physical change

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Answer:

h² = 0.6

Explanation:

Before answering the question, we need to know a few concepts.

<u>Artificial selection</u> is the selecting practice of a specific group of organisms in a population -that carry the traits of interest- to be the parents of the following generations.

Parental individuals carrying phenotypic values of interest are selected from the whole population. These parents interbreed, and a new generation is produced.

<u>The selection differential, SD,</u> is the difference between the mean value of the trait in the population (X₀) and the mean value of the parents, (Xs). So,  

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h² = R/SD

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R = h²SD  

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R = X₀ - X₁

-------------------------------------------------------------------------------------------------------------

Now that we know these concepts and how to calculate them, we can solve the proposed problem.

Available data:  

  • You are selecting rice´s decreased period of maturation.
  • The population of rice has a mean maturation time of 30 days → X₀
  • Parental selected average period to maturation is 25 days → Xs
  • F1 plants mature on average in 27 days → X₁
  • N arrow sense Heritability → h²

According to what we sow previously, we need to find out the value of h².

We know that h² = R/SD, so we need to get R and SD first.  

R = X₁ - X₀

R = 27 - 30

R = -3

SD = Xs -  X₀  

SD = 25 - 30

SD = -5

Knowing this, we can calculate h²

h² = R/SD

h² = -3/-5  

h² = 0.6

 

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<h3><u>Non-Renewable</u><u> </u><u>Resources</u><u>:</u></h3>

The resources which cannot be regenerated after use and get completely exhausted are called Non-Renewable Resources or Exhaustible Resources.

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