Single-celled organisms that do not have a membrane-bound nucleus are called
a. eukaryotes.
b. prokaryotes.
c. golgi bodies.
d. organelles.

This is a biological reaction due to a stimulus. i need this quickly !

Aragonite shells of clams, snails, or scleractinian corals may be preserved unaltered in cenozoic deposits, but they are generally dissolved or recrystallized in older deposits. true or false

How many pounds does the earth weigh?