Number 1 on the graphic refers to nitrogen. What
happens when nitrogen is
breathed in by an organism?

A. It attaches to hemoglobin and is
circulated through the body.
B. It dissolves in the plasma and is
carried to all of the body tissues.
C. It is exhaled.

Which statements correspond to cellular respiration? co2 diffuses passively into the cell. co2 diffuses passively out of the cell. co2 must be pumped out of the cell. o2 diffuses passively when produced inside the cell. o2 diffuses passively when converted to co2. o2 is pumped in and forces co2 out.

Over the past 60 years, many amphibian species have experienced significant population declines and some species have become extinct. scientists suspected that local human activities such as the destruction of wetlands, regional pollution, and deforestation were the main reasons for these losses. however, research over the past 20 years reveals significant amphibian population declines in protected areas of the world, such as nature preserves and parks. these global declines suggest widespread problems including increased ultraviolet radiation, acid rain, and disease. in switzerland, for example, 14 of the 20 native amphibian species are threatened with extinction. chytridiomycosis is a fungal disease first identified in 1998 as a cause of massive amphibian deaths. in some severely impacted populations, a few individuals have survived, perhaps because of some natural resistance. if these resistant individuals continue to survive and prosper, new resistant populations might emerge. this would be an example of the founder effect artificial selection genetic drift natural selection sexual selection

The normal shape of an enzyme is as shown in structure a. if the enzyme’s shape changes to that shown in structure b, what are two consequences of this change?