Star fish, sea urchin and sea cucumber are echinoderms and exhibit radial cleavage. The two tiers of cells of their eight cell embryo are aligned directly over each other. Earthworms are annelids and exhibit spiral cleavage during embryonic development in which upper tier of cells made an angle with cells of lower tier in eight celled embryo.
<span>I think the correct answer among the choices listed above is option C. The organism described most likely is a starfish. This is because annelids and mollusks exhibit spiral holoblastic cleavage while the echinoderms have radial holoblastic cleavage.</span>
I think it lived about 50 million years ago because I know for sure it has to be greater than 10,000 because that is the minimum. It states that fossils are dated more than 10,000 years. Don’t take my word yet, wait for other replies,I could be wrong
Atoms of all elements—except for most atoms of hydrogen—have neutrons in their nucleus. Unlike protons and electrons, which are electrically charged, neutrons have no charge—they are electrically neutral
