Questions

The troposphere is the lowest layer of the atmosphere and where most clouds are. That means all weather is in the troposphere. Almost all weather occurs in the Troposphere, basically, the lowest layer that goes up to about 10 - 15 kms.

Secondhand smoke is very dangerous and creates serious health risks to you and your family members. 

Water is capable of dissolving a variety of different substances, which is why it is such a good solvent.

And, water is called the "universal solvent" because it dissolves more substances than any other liquid

It means that wherever water goes, either through the ground or through our bodies, it takes along valuable chemicals, minerals, and nutrients

DNA - Deoxyribonucleic acid is a type of nucleic acid. The sugar contained in it is called Deoxyribose.

Phage typing is based on the fact that bacterial viruses attack specific cells. Phage typing is a method used for detecting single strains of bacteria. It is used to trace the source of outbreaks of infections. 

Appetite is the desire to eat food, sometimes due to hunger. Appetite is triggered by environmental cues such as the smell or taste of food. Appealing foods can stimulate appetite even when hunger is absent.

Compound word means when two or more words join together to make a single word that gives a new meaning.

Here in the options, Self-evident is the compound word.