What happens to contraction of a muscle cell if some of the Ca2+ that was released during a contraction is still in the cytoplasm (sarcoplasm) when the next stimulus arrives? Group of answer choices The muscle contracts with the same tension generated as during the first contraction, because muscles contract in an all-or-none fashion. The muscle contracts with the same tension generated as during the first contraction, because the number of cross-bridges formed is always the same during a contraction. The muscle contracts with greater tension generated because there will be more Ca2+ in the sarcoplasm after the second stimulation, which will bind to more troponin molecules. The muscle contracts with greater tension generated because more troponin molecules bound means greater myosin-binding sites (active sites) are revealed on the actin, leading to a larger number of cross-bridges formed.

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

Can bacteria reproduce in a way such that when you start out with two bacteria, you get five bacteria? why or why not? * a. yes, because bacteria reproduce sexually, and can produce any number of offspring, just as humans do. b. no, because bacteria grow at an exponential rate. c. no, because when bacteria reproduce, they split into two parts, and two bacteria splitting would result in four bacteria.

The carbon cycle is best defined as a process in which a. carbon changes from inorganic forms to organic forms and back b. carbon is changed into other elements such as oxygen or nitrogen c. carbon is continually created from the sun’s energy by plants d. carbon is consumed and regenerated from other elements such as oxygen and nitrogen