I think that the correct answer would be 2.
The molecules in the air are always creating pressure. Countless molecules collide into everything every second, creating a constant force. Before the air in the balloon is heated, the molecules inside are creating as much pressure as the molecules outside, meaning that the balloon stays at equilibrium and neither expands nor contracts. When they get heated, however, the inside molecules start moving with more force. They create more pressure, causing the balloon to expand outward until the pressure equalizes.
The answer to the first question is C isotonic environment. To help me learn this I memorized that isotonic is equal hypotonic is over hydrated while hypertonic is dehydrated. And for the second question is they move from high to low so C
Tension in the rod is responsible for balancing force due to gravity.
