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.

stratosphere: as the altitude increases, the air temperature increases. the stratosphere has a layer of ozone, called the ozone layer. this layer absorbs most of the ultraviolet radiation from sunlight. this results in the stratosphere being warmer.

i think a) betsy can donate only blood to mark is correct because, mark and betsy have the same blood type. whereas nobody else has b+ blood so betsy can't donate to them.