When did all of the modern animal phyla first appear?
a. about 3.5 billion years ago, following the evolution of photosynthesis, which produced food that forms the basis of food webs.
b. about 540 million years ago, during the adaptive radiation known as the cambrian explosion, due in part to predator-prey coevolution.
c. about 200,000 years ago, following the evolution of homo sapiens in africa.
d. about 475 million years ago, after colonization of land by plants, which newly evolved animals could eat.
e. about 65 million years ago, after the extinction of the dinosaurs, because of the available niches and habitat left vacant by the end-cretaceous extinction event.

B

Explanation:

About 54O mil years ago the Camberian Explosion happened and in Camberian period major animal phyla appear according to fossil records.

1. amino acid refers to the fundamental building block of proteins, comprising of an amino group and a carboxyl group.

2. catalyst refers to any substance, which increases the rate of chemical reaction without being used up in the reaction.

3. a complex molecule containing he genetic code is dna or deoxyribonucleic acid.

4. an enzyme refers to a molecule of protein, which is unique in accelerating up a particular chemical reaction in the biological systems.

5. nucleic acid refers to an sequence of sugars, phosphates, and nitrogenous bases, for example, dna and rna.

6. a protein refers to a large, composite organic molecule comprising of a huge number of amino acids associated together with the of peptide bonds.

7. rna refers to a nucleic acid that takes part in the production of proteins.

8. substrate refers to a compound, which takes part in a chemical reaction, and is chemically modified by the reaction.