Q AQ What type of system is required to maintain the amount of sugar in the blood at a certain level, making sure it does not rise too high or fall too low?

A. one negative and one positive feedback loop
B. two negative feedback loops
C. two positive feedback loops
D. one negative feedback loop

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.

How does natural selection change thephenotypes within a population over time?

Which statement describe events that occur during interphase?