Question

Which of the following animals is the most complex? Base your decision on body plan, structures used to carry out various functions, and structures used to respond to the environment.

A) flatworms
B) hydras
C)sea urchins
D) sponges

Answer 1

so u need some more help

Answer 2

yea, please if it isn't to much to ask

Answer 3

no its not to much

Answer 4

it kinda is a opinion rather thn anything else

Answer 5

really, how so?

Answer 6

It is not an opinion.

flatworms-multicellular, without segments, no specialized respiratory/circulatory tissue, no body cavity, though there is cell layers with a jelly-like substance between them.

hydras-radial body plan, nerve net with no brain or nerve center, no muscles, one opening (mouth/anus), two body layers

sea urchins-radial body plan, no brain (simple nerve ring around mouth). They have a simple circulation system that is open, no heart. multicellular with specialized tissue/cells

sponges-multicellular organism without true tissues. cells can transform into other speciallized cells, but there is no true tissues. They have no recongnizable systems, eg nervous. The two cell layers they have are not held together. Unlike most multicellular organisms the cells can move and change function. Sessile filter feeders

Answer 7

lol "an opinion"