The male fruit fly has an XY profile of the sex chromosomes, and the female has an XX profile of the sex chromosomes.
If a male is white-eyed, then it must have a white recessive allele on his only X chromosome and the red eyed female can be homozygous (having two dominant red eye alleles) or heterozygous (having both a dominant and a recessive allele).
If the female is homozygous then all of the offspring will be red-eyed, and if she's heterozygous then half of the offspring will be white eyed. (see the table provided below)
Answer
HBA HBs
Explanation:
In some parts of Africa, up to 20% of the population are carriers of the sickle cell gene. This suggests that the trait must have a survival value. The carriers of the trait have a much lower susceptibility to malaria than normal individuals. This is because the malaria parasite survives very poorly in sickled red blood cells.
the answer is B.extinction can be related to a failure to adapt to changes in the environment.
Stem cells are what allow planaria to grow and regenerate as the stem cells can change into any of the cells that make up the planaria.