Which of the following make up a plants vascular system allowing it to work as a transport system?
a. it is made up of specailized tubes that move around the plant as it grows
b. it is made up of specailized cells that have thick cell walls
c. it is made up of specailized cells that form straw-like tubes
d. it is made up of specialized cells that divide as the plant grows
thx

Are the earth's ocean floor and continents the same age geologically? why or why not?

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.

Environmental science are unconsidered with methods to preserve natural resourcesa.trueb.false