5) pioneer plant species could be described as those that
a. sprout from seeds after a forest fire.
b. form large forest trees that shade understory plants.
c. are slow to mature, and require a soil with well-balanced nutrients.
d. are small in size, and have highly effective means of dispersing their seeds.

Ans D is the closest answer of this question.

Explanation:

Pioneer species are those species that grow itself, they have small in size and have highly effective means of dispersing their seeds.

true, generally referred to as invasive species given that they have no natural predators in new environment

the relative atomic mass of an element is the mass of one atom of that element, relative to 1/12th of the mass of a  1212c atom. to convert to an absolute mass in kg, it is necessary to multiply by  1.661×10−271.661×10−27.

the relative atomic mass is roughly equal to the number of neutrons, plus the number of protons, in the nucleus of the atom.

for elements with more than one stable isotope (different types of nucleus with different numbers of neutrons but the same number of protons), the quoted mass is usually the average mass, weighted by the relative abundance of the different isotopes.