Which is more efficient at exchanging materials, a small or a large cell?

The gene that causes sickle-cell disease is present in a higher percentage of residents of sub-saharan africa than among those of african descent living in the united states. even though this gene causes sickle-cell disease, it also provides some protection from malaria, a serious disease that is widespread in sub-saharan africa but absent in the united states. discuss an evolutionary process that could account for the different percentages of the sickle-cell gene among residents of the two regions.

Where does all the water go? according to the environmental protection agency (epa), in a typical wetland environment, 39% of the water is outflow; 46% is seepage; 7% evaporates; and 8% remains as water volume in the ecosystem (reference: united states environmental protection agency case studies report 832-r-93-005). chloride compounds as residuals from residential areas are a problem for wetlands. suppose that in a particular wetland environment the following concentrations (mg/l) of chloride compounds were found: outflow, 60.4; seepage, 73.7; remaining due to evaporation, 26.4; in the water volume, 46.8. (a) compute the weighted average of chlorine compound concentration (mg/l) for this ecological system. (round your answer to one decimal place.) mg/l (b) suppose the epa has established an average chlorine compound concentration target of no more than 58 mg/l. does this wetlands system meet the target standard for chlorine compound concentration? yes. the average chlorine compound concentration (mg/l) is too high. yes. the average chlorine compound concentration (mg/l) is lower than the target. no. the average chlorine compound concentration (mg/l) is lower than the target. no. the average chlorine compound concentration (mg/l) is too high.

Environmental science are unconsidered with methods to preserve natural resourcesa.trueb.false