One pound of fat contains 3,500 calories. If you want to lose 25 pounds, for example, how many calories is that?

the bedroo..

any abiotic or biotic factor in an ecosystem that causes a population's size to slow or decrease is a limiting factor.

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".