I’m not sure if this is right but I’m pretty sure it’s C
Define hydrogen bonds( It a weak bond between two molecules) one molecules and goes to electronegative to another.
Near the Earth's surface, the sunlight that does reach the ground warms the Earth, which in turn warms the air immediately above it. So the troposphere is warmest next to the warm ground, and cooler higher up away from the warm ground.
Weak acids such as carbonic or sulfuric acid react with rocks in the ground, such as limestone. Groundwater reacts with limestone and the dissolving of limestone takes place which forms karst features, such as caverns.