act or process bringing change. Exchanges of one set of clothes for another. To go from one train, bus, etc. and go to another.

biological community of interacting organisms and their physical environment. Types of plants and animals in an specific area.

natural colouring matter of animal or plant tissue. Substance that makes things have a certain color. colour something with or as if with pigment.

control or maintain rate or speed of machine or process so that it operates properly.

system of parts in machine. Parts of a machine that performs a certain function.

To make something smaller or less important.

sentence worded or expressed so as to elicit information. What you ask about; issues. To ask for or try to get information.

To find something new that was not known before.

Concerning the body of a person. Health check at the doctors' or hospital.

series of actions towards achieving something. To organize and use data in a computer.

Normal or usual. what is commonplace or standard.

Predominantly photosynthetic prokaryotic organisms containing a blue pigment in addition to chlorophyll; occur singly or in colonies in diverse habitats; important as phytoplankton.