Which of the following describes the formation of air convection currents?

a. molecules in cooler air move faster and farther apart than those in warmer air.
b. cooler air moves in over the warm air and pushes it down.
c. the sun warms the land, which heats the air above it.
d. all of the above

(2) (a) you have a simple circuit that consists of only a battery (δvbat=1.5v) and two resistors with resistance r1=10ω and r2=5ω, connected in series with each other. what is the current running through the battery? (b) you re-arrange your circuit so now r2 is attached in parallel to r1 rather than in series. what is the current running through the battery? (c) you add an additional resistor r3=7ω on the same branch as r2. what is the current running through the battery? (d) what is the power dissipated in r3?