A cell’s rate of exchanging materials with the environment positively relates to its surface area-to-volume (SA/V) ratio. Cell shape also correlates to its function. Also, spherical cells have the smallest surface area compared to all cells of the same volume but different shapes. Which of the following cell types is likely to have the highest rate of material change?

a flat epithelial cell with a diameter of 5 micron
a spherical immune cell with a diameter of 5 micron
a round mammalian oocyte with a diameter of 1 millimeter
a near-spherical intestinal stem cell with a diameter of 8 micron

On a certain portion of an experiment, a statistical test result yielded a p-value of 0.18. what can you conclude? 2(0.18) = 0.36 < 0.5; the test is not statistically significant. if the null hypothesis is true, one could expect to get a test statistic at least as extreme as that observed 18% of the time, so the test is not statistically significant. if the null hypothesis is true, one could expect to get a test statistic at least as extreme as that observed 82% of the time, so the test is not statistically significant. 0.18 > 0.05; the test is statistically significant. p = 1 - 0.18 = 0.82 > 0.05; the test is statistically significant.

Among the following environmental factors, which does not have a long-term impact on the composition of a region's soil? a. kinds of crops grown b. types of fungi present c. topography of the landscape d. variety of species of mammals e. number of freezes occurring annually

Which of the following situations would most likely occur if a human-induced event caused the ocean water to become the same temperature around the world? deep ocean current circulation would increase salt distribution around the world's oceans. surface ocean current circulation would distribute heat around land masses at a faster rate. new, fresher water would float on top of dense salt water and limit thermohaline circulation. some land masses in the northern hemisphere would start to warm up over time, melting snow and ice. runoff of surface freshwaters and rainfall would no longer have an effect on the salinity of ocean waters.