Which cellular structure do organisms in the kingdoms eubacteria, archaebacteria, and protista have in common?
a. a nucleus

b. a cell membrane

c. a circular chromosome

d. a mitochondrion

I believe the answer is B.

Explanation:

Hope my answer has helped you and if not i am sorry.

answer; ///i believe the answer your looking for is (ribosomes);

the most common energy conversion is from kinetic energy to potential energy, and then from potential energy to kinetic energy.

later on comes the heat energy, mechanical energy, and other energy conversions.

this energy conversion is so common that we can find it in our day to day lives as well.

- one of the most common energy conversions involves the changing of potential energy to kinetic energy or kinetic energy to potential energy