Which of these statements is true about the evolution of multicellularity in eukaryotes?
a. it occurred only once, in the common ancestor of all eukaryotes.
b. it occurred only once, in the common ancestor of all multicellular eukaryotes.
c. it occurred only once, in the animal lineage.
d. it occurred independently multiple times in several eukaryotic lineages.
e. we don't have enough evidence to support any of the current hypotheses

D) It occurred independently multiple times in several         eukaryotic lineages.

Explanation:

The evolution of multicellularity in eukaryotes are occurred multiple times and it has evolved atleast in 25 eukaryotic lineage. Multicellularity evolution produced in complex organisms and the biology history on the earth are drastically shaped in the ecology planet. Multicellularity is one of the reason in which such complex biodiversity existed now.

they deliver oxygen to the blood