Answer the following question given this paragraph: As with the hydrogen-ion concentration, the concentration of the hydroxide ion can be expressed logarithmically by the pOH. The pOH of a solution is the negative logarithm of the hydroxide-ion concentration. Q: The negative logarithm of the hydroxide-ion concentration of a solution is called? Choices: - the hil - the hop - the piel - the poh A:
the poh

Answer the following question given this paragraph: The ancestor of plants is green algae. This picture shows a close up of algae on the beach. Q: Name the plant considered to be the ancestor of plants? Choices: - brown algae - ferns - grass - green algae A:
green algae

Answer the following question given this paragraph: A cold front occurs when a cold air mass runs into a warm air mass. This is shown in Figure below . The cold air mass moves faster than the warm air mass and lifts the warm air mass out of its way. As the warm air rises, its water vapor condenses. Clouds form, and precipitation falls. If the warm air is very humid, precipitation can be heavy. Temperature and pressure differences between the two air masses cause winds. Winds may be very strong along a cold front. Q: What occurs when a cold air mass runs into a warm air mass? Choices: - an occluded front - a stationary front - a snow day - a cold front A:
a cold front

Answer the following question given this paragraph: Q: Plants supply, ultimately, most of the food eaten by terrestrial animals, along with what gas? Choices: - hydrogen - nitrogen - carbon dioxide - oxygen A:
oxygen