The image below shows a jungle with birds and mammals. Which of the following explains why some birds have brightly colored feathers?

- Natural selection changed bird populations by causing adaptations for survival.
- Vegetation used to be different colors, and the birds adapted to match the colors.
- Birds adapted by changing their feather colors to compete with other bird species.
- Bright feathers attract mates and is the favored trait through natural selection.

Acell in the human nervous system whose primary function is to form myelin and the blood-brain barrier, respond to injury, remove debris, and enhance learning and memory is called a(n) cell.

Duchenne muscular dystrophy is a serious condition caused by a recessive allele of a gene on the human x chromosome. the patients have muscles that weaken over time because they have absent or decreased dystrophin, a muscle protein. they rarely live past their twenties. how likely is it for a woman to have this condition? a) women can never have this condition. b) one-fourth of the daughters of an affected man would have this condition. c) one-half of the daughters of an affected father and a carrier mother could have this condition. d) only if a woman is xxx could she have this condition.

What are they five steps of cloning?