Which of these statements about particulate matter less than 2.5 microns in diameter is true? A. They're less of a threat than particulate matter that's 10 microns in diameter.
B. They can cause heart and lung disease.
C. They're produced from nitrogen gas (N2).
D. They're the size of a human hair.

Vegetation that grows along the floors of tropical and temperate forests is called undergrowth. how is the undergrowth of a tropical rain forest most likely to differ from the undergrowth of a temperate forest? a. a tropical rain forest's undergrowth most likely experiences periods of dormancy during colder weather. b. a tropical rain forest's undergrowth most likely experiences periods of dormancy during rainy weather. c. the undergrowth of a tropical rain forest most likely requires less sunlight. d. the undergrowth of a tropical rain forest most likely requires more sunlight.

You have a solution that contains phospholipid vesicles in a test tube. these vesicles have phospholipid bilayers, but do not contain any membrane transporters. you add a number of different molecules to the solution, and wait a period of time for them to equilibrate. if you could measure the concentration of each molecule, for which of the following would you expect to measure equal concentrations inside and outside of the vesicles? assume for this question that the overall osmolarity inside and outside the vesicles is the same (that is, there is no appreciable diffusion of water across the membrane). (select two answers) an amino acid with a hydrophobic side-chain a small non-polar molecule a negatively charged ion a small polar molecule a small lipid hormone

All living organisms are composed of a. only one cell. b. at least 100 cells. c. at least three cells. d. one or more cells.