in a population of rats, most of the rats fall within a certain size range, Small rats are too weak to survive, and big cats are too easily caught as prey, leaving mostly medium sized rats as survivors. What is this an example of?

Which symbols below represent the ions found in the glass of water ? a. oh- and h+ b. co2 and o2 c. o2 and h2 d. nh3- and h+

Which statement correctly describes other ways in which nebulae and stars are different? a. a star always has a higher density than a nebula. b. stars can form inside a nebula but a nebula can never be produced by any star. c. stars can never form inside a nebula but a nebula can be produced by any star. d. a nebula always has a higher density than a star. reset submit

Which of the following is an eon in the time scale? phanerozoic proterozoic archean all of the above