Using biofuels instead of fossil fuels because biofuels are renewable is an
example of

Using biofuels instead of fossil fuels because biofuels are renewable is an example of renewable sources.

Explanation:

Biofuels is an example of renewable sources because biofuels is extracted from different parts of plants such as leaves and stem etc and plants is grown again and again and biofuels is again extracted from it. So we can say that biofuels is a renewable source.

i think a, hope it .

explanation:

substituting a hydrogen atom with a halogen in a hydrocarbon:

- the single bond remains single. a is wrong.

- the bond with hydrogen is as strong as with a halogen. c is wrong

- a hydrocarbon is saturated if there is no double bond. we do not know that so d is wrong.

- carbon will always have four valence electrons. e is wrong.

by elimination, the correct answer is b. the boiling point of the new compound increases.