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
