20 points
1. some cancers have a genetic component to them. if a parent has a cancer, the children are more likely than the average population to develop the cancer. why might this be?

a. cancers require more than one mutation to occur.
b. cancers are inherited but remain dormant until a certain age.
c. parents and children are often exposed to similar environmental factors.
d. cancers are often recessive traits and require alleles from both parents.

5. during the cell cycle, a cell grows

a. and dies.
b. and divides.
c. without completing cytokinesis.
d. without completing mitosis.

Which pedigree symbol is used to represent a female carrier of a recessive x-linked trait? поө0 || save and exit submit

Which statement is true about the cell theory? a) it is well-supported by evidence. b) it is unchangeable and permanent.

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