What is the answer??

3 you use elements instead of numbers and arrows instead of equal signs

actually it would be more like word problems you have 4 apples plus 3 oranges yields 7 apple orange things but it doesn't yield 7 of them it would be an equal ratio of moles of the fruits

4 the arrow is an equal sign

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.

air

in a tire you fill a tire with air

then a couple days later you check the air pressure in the tire

hope this mark me brainliest