Which of the following combinations correctly matches a phylum to its description?

a. echinodermata - bilateral symmetry as a larva, water vascular system
b. nematoda - segmented worms, closed circulatory
c. cnidaria - flatworms, gastrovascular cavity, acoelomate
d. platyhelminthes - radial symmetry, polyp and medusa body forms

Elephants in the savanna regions of africa dig holes in dried up river beds to reach water lying just below the surface. these holes provide drinking water for other animals as well. so, without the elephants, many animals might otherwise die from lack of water during the dry season. the location in which the elephants live is an example of a/n and the role they play in creating water holes is an example of a a) ecosystem; habitat b) community; niche c) habitat; niche d) niche; habitat

2. given that most biochemical (other than coal) rocks react with hydrochloric acid, what does that tell you about organisms?

How does the nervous system affect the excretory system?