The first heart sound, "lubb," is caused by the . The first heart sound, "lubb," is caused by the . closing of the atrioventricular valves regurgitation of the atrioventricular valves closing of the semilunar valves blood flowing into the ventricles

When is a hurricane considered to have made landfall? a. when at least one inch of rain occurs b. when the eye reaches the land mass c. when the outer wind bands make landfall d. when it moves inland from the coast

Identify characteristics of energy from the sun. check all that apply. almost all of the energy on earth comes from the sun. energy from the sun is known as mechanical energy. the energy in fossil fuels originally came from the sun. plants convert the energy of sunlight into chemical energy.

For the strategies below, decide whether they are best described as demand-side solutions or supply-side solutions to meeting human needs for fresh water. remember that a demand-side solution reduces demand for fresh water, whereas a supply-side solution increases the supply of fresh water. (a) damming a river to create a reservoir (b) desalinating seawater (c) a nation invading a neighboring country to access their rivers (d) raising water prices for consumers and businesses (e) providing tax breaks for companies that use less water (f) replacing inefficient irrigation with more-efficient drip irrigation to grow crops (g) requiring low-flow showerheads in all new homes