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.

In the first situation: the mechanism of covection is the main form of heat transfer when warm air from a heater moves around and upward.

In the case of the metal pan the mechanism of heat transfer is conduction.

In the case of sunburn the mechanism is radiation.

In the case of an ice cube melting in a hand, conduction is the most important mechanism.

Mass is the amount of matter in an object.  weight is the measurement of the pull of gravity on an object.  say for example, you travel to the moon which has a different gravitational field compared to the gravitational field of earth. (gravitational fields: earth = 1, moon = 0.165)  now when you are on the moon, the pull of gravity on you is different than on the earth. and as weight is the measurement of the pull of gravity on an object, that means yes, your weight can and will change on the moon.  however, on the moon, on earth or even on jupiter, the amount of mass inside of you remains the same. meaning your physical mass remains constant.  in conclusion it is possible for your weight to change as your mass remains constant.