Answer:
"Brachiopoda"
Drosal and ventral valves; Individuals resemble clams; May have no anus
"Bryozoa"
Possesses a chitinous zoecium; Anus opening near mouth; Colonies resemble moss
The term that can be used to describe evolution by natural selection is SCIENTIFIC THEORY.
Theory means "the best explanation so far."
Scientific theory is a work in progress. It is a well-substantiated explanation of some aspect of the natural world that is acquired through the scientific method, and repeatedly confirmed through observation and experimentation.
So that it can sustain different life that requires different environments. Angler fish, for example, require a dark and cold environment to thrive while tuna require a light and warm environment.
