Instructions: select all the correct answers. which sentences describe disadvantages of burning fossil fuels instead of using hydrogen fuel cells? 1.burning fossil fuels contributes to climate change. 2.burning fossil fuels takes place inside expensive fuel cells. 3.fossil fuels aren’t widely available, but pure hydrogen is. 4.fossil fuels are nonrenewable.

The correct answer is 1 and 4.

Burning of fossil fuels releases harmful gases to the atmosphere which leads to climate change. Burning of hydrogen gas releases water which has no negative effect on climate.

Burning of both fossil fuels and hydrogen takes place inside expensive fuel cells.

Fossil fuels are widely available and easy to locate whereas hydrogen is available in the combined form with other elements. Hydrogen are not found in pure form on earth.

Fossil fuels are non-renewable source of energy which means they cannot be replaced in short time.

when it gains or loses electrons

kepler used the data from tycho blahe (his mentor) to construct the laws of planetary motion.