If a sample contains 100 g of Carbon-14, how much Carbon-14 will be left after 3 half lives?

According to the theory of punctuated equilibrium, at what rate does speciation occur? species change depending on the rate of natural selection. after periods of stasis, new species evolve relatively rapidly. species change slowly and eventually form new species. some species change quickly and others change slowly to balance the overall rate.

I’m doing some practice exam questions for biology, and i’m not sure how to do these 3 parts to the question.

Which of the following typically characterizes a tropical rainforests