What was the probable order of occurrence of these derived traits?

Question

What was the probable order of occurrence of these derived traits?

A. Multicellularity, segmented body, hair, placental reproduction

B. Multicellularity, segmented body, jaws, limbs, placental reproduction

C. Segmented body, multicellularity, jaws, limbs, placental reproduction

D. Segmented body, hair, placental reproduction, multicellularity

Answer 1

B.  multicelluarity must come before segmented body...

placental reproduction doesn't show up--as far as i'm concerned until the rise of animals that don't lay eggs... ie... mamals...

It can't be A... because some reptiles give live birth...meaning that placental reproduction must have come first...

it can't be c because there must be multiple cells before anything that can be considered a body can develop at all....

it can't be d because multicelluraity must be first...

Answer 2

I would say b.... have to be multicellular before you can have a segmented body, etc.

Answer 3

A is the correct choice.  Hypercellularity developed first, then segmented bodies.  This can be seen in the structure of life.  Multicellular creatures (e.g. amoeba) are "lower on the chain" than creatures with segmented bodies (e.g. ants or wasps).  Segmented bodies are in turn "lower" than hair or placental reproduction.  Since marsupial have hair but do not use placental reproduction (at least not to full term) and there are examples such as the platypus and echidna (spiny anteater) which have hair but lay eggs I would put this next in the stage of development and placental reproduction last.

Answer 4

B. Multicellularity, segmented body, jaws, limbs, placental reproduction