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.
Answer:
Charge, 
Explanation:
It is given that,
The number of electron in a RBCs, 
We need to find the total charge of these electrons in the red blood cell. Let it is q. Using the quantization of charge as follows :
q = ne
e is the change on electron
So, the net charge is 
.
Answer:
If the frequency is doubled the wavelength is only half as long.If you put your fingertip in a pool of water and repeatedly move it up and down,you will create circular water waves.
Hope this helps!!!
Energy transformation or conversion
