Answer:
In the course of evolution mammals are the animals which are evolved recently as compared to other groups such as fish, amphibians, or reptiles.
In addition, fur or hairs on body, mammary glands, middle ear bone, warm-blood, et cetera are the characteristics of mammals.
These characteristics were evolved during the course of evolution; they were not present in ancestral organisms.
However, tail, gill pouches, et cetera are characteristics of our ancestral groups. Thus, characters can be sometimes observed in mammals.
But mammals characteristics can not be observed in organisms which were evolved before mammals such as fishes, amphibians, reptiles, et cetera.
Answer:
The correct answer is : the female chromosome
Explanation:
- According to the question, it is mentioned that R is a dominant allele, responsible for the red eyes.
- RR is a genotype for Red eyes.
- A fruitfly has a diploid genotype which means each trait is represented by a pair of chromosomes.
- In the above question, the dominant red eye colour trait is represented by the pair of chromosomes RR.
- Therefore, XX must represent another trait.
- By convention, a pair of X chromosomes (XX) represent a female and a combination of X and Y chromosomes (XY) represents a male.
- Given XX genotype represent a female fruitfly chromosome.
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