*Question*
Hydropower requires damming a river, and another source of energy is hydropower. Given these facts, what is a source of energy among the following options: - fossil fuels - cooking - damming a river - sleeping - napping - Electrical energy - our nearest star - sunlight
**Answer**
damming a river

*Question*
Agasoline lawn mower converts gasoline into motion, and gasoline is made up of hydrocarbons. Given these facts, a lawn mower converts _ into motion among the following options: - kinetic energy - flow of electrons - hydrocarbons - energy - Greenhouse gasses - heat energy - fossil fuels - Greenhouse gases
**Answer**
hydrocarbons

*Question*
Male dogs use pheromones in urine to mark their territory, and generally, pheromones are volatile substances. Given these facts, male dogs use what in their urine to mark their territory among the following options: - hydrocarbons - volatile substances - kinetic energy - an area swollen with pus - Chemical energy - competing for resources - add a solute - Positive charges
**Answer**
volatile substances

*Question*
Agreenhouse is used to protect plants by keeping them warm, and temperatures go from warm to hot. Given these facts, what is used to protect plants by keeping their temperature among the following options: - a white house - energy - an electric stove - a microwave - electricity - a thermometer - exoskeleton - a greenhouse
**Answer**
a greenhouse