Carbon is so abundant in living things even though oxygen is the most abundant element on Earth because carbon atoms can bond with one another to make chains and cyclic structures whereas oxygen atoms cannot form chains or cyclic structures.
The correct answer is the first option.
The human activity that impacts the weather on Earth negatively is the burning of fossil fuels. When burning the fossil fuels, the temperature on Earth is increased. This causes Greenhouse Gases. The EPA is trying to cut down on the burning of fossil fuels by closing down power plants ran off of coal.
Really really really small