Why the effect of gravitational force is more in liquid than in solid?

What happens in a global convection cell

When a bicycle coasts uphill, it moves slower and slower as it climbs. why? a. its kinetic energy is transforming into heat energy. b. its potential energy is transforming into kinetic energy. c. its kinetic energy is transforming into potential energy and heat energy. d. its potential energy is transforming into kinetic energy and heat energy.

Why is rain likely when warm, moisture-laden air meets cold air? a) the lighter warm air will rise and cool down, causing condensation and rain. b) the cold air moves faster and pushes the warm air away, causing condensation and rain. c) the moisture in the warm air condenses on contact with the cold air, causing rain to fall. d) the cold air mixes with the warm air, reducing its temperature causing moisture to condense.