In a classroom experiment, a student rubs a comb against her hair. the comb is then brought near bits of paper resting on a surface. which of these can be concluded if the comb picks up the bits of paper?
a)
the comb is an insulator, but paper conducts electricity.
b)
the comb had a net charge on it, and it attracted a neutral object.
c)
the comb was left uncharged, and it attracted a positively charged object.
d)
the comb was positively charged, and it attracted a negatively charged object.

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 negative impacts of nonnative species generally outweigh the positive impacts

What is the main function of the central vacuole in a plant cell? a. absorbs energy from the sun to produce food b. holds water and maintains turgor pressure c. breaks down molecules to release energy d. contains the cell's genetic material