Help plz: 6. Describe the range of variation in the nervous systems of invertebrates.

7. Distinguish among asymmetry, radial symmetry, and bilateral symmetry.

1. Although most invertebrates have a nervous system, the complexity of the system varies from one organism to another.

Some invertebrates such as the hydra and starfish have a simplified system of nerves, which is called a nerve net. It consists of just nerves, capable of sense and touch only. Meanwhile, other invertebrates such as the planarian have a more developed nervous system, complete with a brain and nerve cord.

2. The key difference between radial and bilateral symmetry is that radial symmetry generates identical body halves around the central axis whereas bilateral symmetry generates only two sides as left and right.

Explanation:

the generally accepted parts of modern cell theory include: all known living things are made up of one or more cells. all living cells arise from pre-existing cells by division. the cell is the fundamental unit of structure and function in all living organisms.