Why do multicellular organisms generally live longer than unicellular organisms?

Which flexible structure that supports the nerve cord and led to the backbone

Why do you suppose the structural polysaccharide cellulose does not contain branches?

How does the fossil record provide evidence that the modern whale evolved from the anthracotheres? a) the modern whale looks like their ancestor the anthracotheres. b) the modern whale has all of the same structures as their ancestor. c) there is not enough evidence to suggest the the modern whale evolved from the anthracotheres. d) the anthracotheres has a structure that is still present in the modern whale, but is no longer of use to the modern whale.