Answer:
Option D, Number of limbs
Explanation:
Options for the question
a. Birth weight
b. Hair color
c. Number of offspring
d. Number of limbs
Solution
Variation within a species is caused due to genetic differences governed by varying allele frequencies and duet to environmental factors that somewhere effect the expression of the genetic potentials thereby causing phenotypic variation.
Number of limbs is a physical characteristics, very unlikely governed by genetic variation. While factors such as hair color (grey, black, white etc.), height (tall, short, medium) etc. are governed by genetic variation as a result of which they have several phenotypic variations.
Hence, option D is correct
Crossing over contributes to genetic variation by exchanging chromosomal segments between non-sister chromatids of homologous chromosomes.
What is crossing over?
- Crossing over is the exchange and recombination of genetic components between the homologous chromosomes.
- This occurs in the pachytene stage of the meiosis-1 of the meiotic division.
- Crossing over occurs with the help of an enzyme and the enzyme responsible for crossing over is called Recombinase.
Thus, crossing over contributes to genetic variation by exchanging chromosomal segments between non-sister chromatids of the homologous chromosomes.
Learn more about crossing over: brainly.com/question/927405
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The correct answer is vitamins and proteins.
Using the supplements for dog is important in order to make the muscle growth and to strengthen the tissues.
Vitamins, such as Vitamin C, which is required for a dog to support collagen production or Vitamin E which has antioxidant function.
