Questions

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.

Database provides necessary means to achieve this abstraction. By structure of a database we mean the data types, relations, and constraints that should hold on the data.

The atmosphere is a mixture of several gases. Nitrogen is the most abundant gas in the atmoshere and oxygen is next to it. It is 78% in the atmosphere and 21% is oxygen. Remaining 1% is all other gases like argon, hydrogen, neon, etc...

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.

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

RAM stands for Random Access Memory.

The statement "A communist government is led by one political party" is what best defiines a communist government. Here in this type of government, the power is in the hands of the one political party and it only controls the political and economic systems of the country/state.