The bottleneck effect is used to describe an event where a population decreases. one example involves the northern elephant seal. they have a reduced genetic variation due to a population bottleneck humans inflicted on them in the 1890s. hunting reduced their population size to as few as 20 individuals at the end of the 19th century. their population has since rebounded to over 30,000, but they have much less genetic variation than a population of southern elephant seals that was not so intensely hunted. which phrase best explains this change if gene frequency? a) gene flow b) speciation c) genetic drift d) natural selection

Salmonella typhimurium is a food-borne bacterial pathogen that can cause severe gastrointestinal disease. salmonella is often phagocytosed by macrophages that normally destroy bacterial pathogens, but this bacterium is somehow able to prevent the complete maturation of phagolysosomes. salmonella is able to tolerate the low ph of phagolysosomes, and in fact responds to the drop in ph by secreting toxins that interfere with other cellular responses. which of the following differences would you expect to contribute to the survival of a bacterium within an salmonella-containing phagosome, compared to a healthy phagolysosome? decreased activity of acid hydrolases increased activity of acid hydrolases decreased import of h+ ions increased import of h+ ions my guess is decreased activity of acid hydrolases but i'm not sure.

The intervention of extraterrestrials has been used to explain the bermuda triangle, a region of the atlantic ocean where ships and planes are frequently lost, leaving no evidence behind. how would this explanation best be characterized?

When a chemical spill has occurred on your clothes you should 1. scream for 2. run under the shower and turn it on 3. use the eye wash station 4. grab the first aid kit