Deshawn is studying homeostasis and circulation. to organize his findings, he constructs two models of the human heart, veins, and arteries:
one to represent a non-smoker, and one that includes attributes typically found in a smoker. by comparing the two models, which relationship of
cause and effect can deshawn best explain?
a. contractions of the heart move blood through the circulatory system.
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b. smoking causes changes to homeostasis throughout the body.
o
c. smoking damages the function of the circulatory system.
d. blood flows in one direction only through the circulatory system.

Read the following scenario to answer the following question. 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. when most populations of a wide-ranging amphibian species are lost and the few remaining populations are widely separated, we expect to see that a. the founder effect becomes increasingly important b. microevolution no longer occurs c. gene flow between populations is reduced d. artificial selection becomes a greater factor in microevolution

Why do we perceive objects as retaining their brightness under different lighting levels?

Why did adult crab numbers decline in he ecosystem, even though sea stars were still available?