Which of the following is the best example of natural selection? (1) A cheetah living in a zoo lives 10 years longer than average.
(2) The shell of a crab becomes harder over time as a result of being hunted by a predator.
(3) A person's muscles become firmer from riding a bike for exercise.
(4) A population of a rabbit's decreases in number as some move to another area.

Parasitism could be considered a form of which of these types of relationships? -mutualism -commensalism -predator-prey -mimicry

The human genome project is devoted to mapping the general dna sequence of our species. this could lead to the development of new medicines, as well as the possibility of using gene therapy to treat certain diseases. however, there are some ethical issues surrounding the mapping of individual genomes. one concern is a) that your genes may change over time, making the project useless. b) that insurance companies could discriminate based on genetic make-up. c) that since this has never been done before, we should probably not do it now. d) that sequencing our individual genomes is so expensive, it is a counter-productive strategy.

How does the carbon cycle involve an exchange of carbon