In which of these situations is convection most likely the main form of heat transfer?

warm air from a heater on the first floor of a house moves to the upper floors.

the sides of a metal pan become hot when the pan is placed on a stove burner.

a person gets a sunburn from lying on the beach too long.

an ice cube melts when a person holds it in his hand.

About 3% of the water on earth is freshest. only about 40% of that freshwater is available for human use. why is so much freshwater unavailable for human use?

What rule is used to determine how many covalent bonds an element can form? a. the number of covalent bonds is equal to six c the number of covalent bonds is equal to five minus the group number plus the group number b. the number of covalent bonds is equal to eight d. none of the above minus the group number select the best answer from the choices provided

What is the energy in joules of a mole of photons associated with visible light of wavelength 486 nm?