Why is the cell membrane described as being selectively permeable?
a. it allows anything to enter and exit the cell.
b. it allows nothing to enter or exit the cell.
c. it allows only water to enter the cell.
d. it allows needed materials to enter the cell and wastes to leave the cell.

Penelope studies how the structure and function of the nervous system is related to behavior. she is a psychologist

The embryos of a bird, a reptile, and a mammal are similar in appearance. how does comparing the physical appearance of embryos of different species support the theory of evolution? a. it shows that these organisms share a common ancestor. b. it provides evidence that these organisms eat the same foods.c. it shows that these organisms share the same habitat.d. it provides evidence that these organisms suffered a genetic mutation.

Asegment id dna that is artificially created from two or more organism through use of dna enzymes in a laboratory is called a segment of dna that is artificially created from two or more organisms through use of dna enzymes in a laboratory is called