Animals in the higher trophic levels generally share two characteristics. they are typically
a) larger in size and fewer in number
b) larger in size and more in number
c) smaller in size and more in number
d) smaller in size and fewer in number

in 1859, charles darwin set out his theory of evolution by natural selection as an explanation for adaptation and speciation. he defined natural selection as the "principle by which each slight variation [of a trait], if useful, is preserved".

the atmospheric gas that forms a mild acid when dissolved in water is called carbon dioxide. the correct answer is a. 2.) chemical weathering would cause an inscription on a marble headstone to become harder and harder to read over time.