Which of these is a disadvantage of using natural gas A It is not considered safe to use in homes. B Scientists have developed new ways of extracting it C It burns less cleanly than other fossil fuels D Extraction through fracking can contaminate groundwater

A

Explanation:

Natural gas is flammable. A natural gas leak in a house can cause potential fires, and inhaling the gas can cause natural gas poisoning.

* Answer B: The fact that scientists have developed new ways of extracting natural gas - is an advantage, not a disadvantage.

* Answer C is wrong, because compared with some other fossil fuels, natural gas emits the least amount of carbon dioxide into the air when combusted -- making natural gas the cleanest burning fossil fuel of all.

* Answer D: the content of the statement is about the production process, not about using of natural gas.

Hope this answer can help you. Have a nice day!

your answer would be a. 12.5 kg

nuclear fission produces elements that are heavier than helium.

the elements that are used in nuclear fission and their products are much heavier than helium.