Which of the following is true of eukaryotes but not of prokaryotes?
a. they do not have membrane-bound organelles
b. they must contain a nucleus
c. they are always single-celled
d. they must be multicellular

The correct answer is B. They must contain a nucleus

Explanation:

One of the characteristics that make eukaryotes different from prokaryotes is that eukaryotes contain membrane-bound organelles including a nucleus, which is the organelle that controls most functions in the cell. Besides this, eukaryotes have other organelles such as lysosomes or Golgi apparatus, while prokaryotes lack these organelles. Moreover, prokaryotes are unicellular while eukaryotes can be unicellular or multicellular. Thus, the correct statement of eukaryotes but not of prokaryotes is "they must contain a nucleus".

i believe the correct answer from the choices listed above is the first option. the scientists need to look at the   validity of data, claims, hypotheses, and observations before  developing an argument. they base their arguments on facts that are present and they make sure they have proofs. 

explanation:

lunar landing mission. apollo 11 was the first manned mission to land on the moon. the first steps by humans on another planetary body were taken by neil armstrong and buzz aldrin on july 20, 1969. the astronauts also returned to earth the first samples from another planetary body.

explanation: