Which of the following best describes scientific theory?

a.) it cannot be changed
b.) it explains very few observations
c.) it is basically speculation
d.) it may change

D.

Theories always change. That's why science always changes

explanation:

for  example, forests have higher evapotranspiration than other ecosystems,  such  as grasslands, because of their deeper roots and greater leaf area. thus forests have a net moistening effect on the atmosphere and become a moisture source for downwind ecosystems.

the answer is trees if i'm not mistaken