Carbon dioxide levels in the blood and cerebrospinal fluid affect blood ph. this enables the organism to sense a disturbance in gas levels as a. the brain directly measures and monitors oxygen levels and causes breathing changes accordingly. b. the brain alters the ph of the cerebrospinal fluid to force the animal to retain more or less carbon dioxide. c. the medulla oblongata, which is in contact with cerebrospinal fluid, monitors ph and uses this measure to control breathing. d. stretch receptors in the lungs cause the medulla oblongata to speed up or slow breathing.

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.

Look at the following answer choices and determine which belongs in the both category. testable, can be disproven explains natural phenomena, has evidence to support it prediction, tentative, one or more scientists working together well established, many different scientists working independently, highly reliable

Dna and rna share a number of similarities,but they also differ in certain aspects of their structure. wich nitrogenous base is found in rna but is not found in dna