1. describe the structure and function of the cell wall of a plant cell. 2. The nucleus is a round, double - walled structure often found in the center of both plant and animal cells. What are the TWO primary function of the nucleus?
Please answer as quick as possible.

Plz ! a frog has a genetic mutation in skin cells that causes part of its skin to turn orange the frog will not pass this genetic mutation onto its offspring because, a. the offspring will inherit skin cells from the other parent. b. mutated skin cells cannot divide and produce daughter skin cells. c. skin cells do not contribute genetic material to sex cells. d. parents do not contribute genetic material to their offspring.

To answer this question, researchers studied populations of the dusky salamander (desmognathus ochrophaeus) living on different mountain ranges in the southern appalachian mountains. the researchers tested the reproductive isolation of pairs of salamander populations by leaving one male and one female together and later checking the females for the presence of sperm. four mating combinations were tested for each pair of populations (a and b)—two within the same population (female a with male a and female b with male b) and two between populations (female a with male b and female b with male a). the proportion of successful matings for each mating combination was measured. for example, when all the matings of a particular combination were successful, the researchers gave it a value of 1; when none of the matings were successful, they gave it a value of 0. then the researchers calculated an index of reproductive isolation that ranged from 0 (no isolation) to 2 (full isolation). the reproductive isolation value for two populations is the sum of the proportion of successful matings of each type within populations (aa + bb) minus the sum of the proportion of successful matings of each type between populations (ab + ba). the table provides data for the geographic distances and reproductive isolation values for 27 pairs of dusky salamander populations.

People with one sickle cell allele are not likely to get malaria. what is this an example of?