father or mother. Person's, animal's mother and father. be parent to.

persist in activity.

To gain knowledge by doing things.

substance used to stimulate production of antibodies and provide immunity against diseases.

maintenance of law and order by police force. To control an area, or group with a police force.

1,000,000.

person who watches or notices. People whose job it is to watch or notice things.

make suffering, deficiency, or problem less severe.

each of four equal or corresponding parts into which something is or can be divided. One of four equal parts of some things. To split something into four equal parts.

cause, explanation, or justification for action or event. Explanations for why some things occurred or was done. think, understand, and form judgements logically.

Anxiety caused by difficult problems. To apply force to something.

person or organization that employs people. People or firms that hire workers.

Very strong uncontrollable emotion, e.g. delight. To carry things from one place to another.

blown by wind with great force. control and operation of motor vehicle. To push or hit an object into something else.

To know someone or something because you have seen or heard him or her or experienced it before.