When two or more substances combine, but each keeps it own properties, the new combination is called a (an)

The new combination is called a mixture.

In mixtures, since the substances are not chemically combined together, they still remain their own physical and chemical properties, and can be separated by simple physical methods such as filtration or distillation.

On the other hand, if the two or more substances are combined where they get new properties, the new combination will be called a compound.  They cannot be separated by physical methods, but chemical methods such as heating or electrolysis.

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.

d) a person who learns about the world by observing it.

explanation:

scientist are people who discover why and how things are done and made in the world.