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.
Motivation is an encouragement to do or achieve something
intensity of a star is inversely depends on the square of the distance from the star
we can say it is given as

here we know that

also we know that

now we will have



so other star is at distance 60 Light years
Answer:
speed = 7.9 m/s
Explanation:
speed = total distance / time taken
speed = 300 / 38
speed = 7.89473684 m/s
to the nearest tenth
speed = 7.9 m/s
Newton’s second law of motion states that when a force acts on an object, the object’s acceleration is equal to the net force divided by the object’s mass, and is in the same direction as the net force.