How do evolutionary developments of the trilobites represent stability over the long term, and change over the short term ?

What are the formed elements (cell or parts of cell) in blood and what are their functions ?

The fish shown above is a tarpon. it is a fast-swimming and powerful open-water fish. its closest relatives, oddly, are burrow-dwelling conger eels that stay on the bottom. both eels and tarpon developed from snake-like larvae that float in the plankton during the first stages of life. once they mature, tarpon and eels are not found near one another in the ocean. the tarpon and the eel illustrate all of the following except

How does a gymnosperm prevent itself from pollinating the same tree