Based on what you know about natural selection, which of the following must be true if evolution is the explanation for what the grants have observed over time on daphne? select all that apply.

food must be plentiful for all birds.
beak depth and length must be heritable.
beak depth and length must show variation among individuals of a single species.
beak depth and length must affect survival and/or reproduction of birds.
over time, individuals can evolve to better fit the environment by changing heritable traits.
the beaks of individual birds can change depending on what food is available.

Which would best keep the oxygen cycle stable? a. cutting down jungles to create farmland b. eliminating parks in large cities c. dumping toxic chemicals into the ocean d. reducing the amount of deforestation d. reducing the amount of deforestation

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.

Which of the following is a common response to cell signaling?