Which characteristic is necessary for natural
selection to occur in a species?
(1) stability
(2) variation
(3) complex cellular organization
(4) a very low mutation rate

What type of weather does tropical continental air bring in summer? hot and cloudy cool and sunny hot and sunny cool and cloudy

How much time has elapsed from the very beginning of "the memior of the conquistador bernal diaz del castillo" to the end? a. castillo's whole life b. a quarter of an hour c. a few weeks d. a decade

The basic types of tissue in the human body are