To think or consider about something over time.

A location on a map. To cite a piece of research in speech or writing.

for reason that.

band of colours, as seen in rainbow, produced by separation of components of light. The wavelengths of colors from red to violet.

picture or diagram made with pencil, pen. To get closer to or approach something or someone. To influence a person's involvement in something.

having become yellow. To turn yellow, often due to aging.

used for emphasis with following adjective functioning as adverb. Thing that is not yet known or named.

in way that is not habitual or common.

Protecting the environment or a species.

matter. Supplies or data needed to do certain things.

Being difficult to deal with or fix. thing that constitutes problem.

person who is studying or has expert knowledge of one or more of natural or physical sciences. People who are trained in a science.

able to stick fast to surface or object. A substance used for gluing one thing to another.

Hiding your true character to mislead. To hide something so that it cannot be seen.

body's relative mass or quantity of matter contained by it, giving rise to downward force. Metal object to measure how heavy something is. hold something down by placing heavy object on top of it.