biology

A person or thing that is not known, recognized, or familiar. It often refers to a mysterious situation or a person who has not yet achieved fame or success.

A preposition used to show a relationship between a part and a whole, or to indicate belonging and origin. It connects a noun or pronoun to another part of the sentence to specify which one or what kind.

A preposition used to indicate position within a container, a space, an area, or a period of time. It describes being surrounded by something or being inside the boundaries of a location.

A third-person singular pronoun used to refer to an object, animal, or situation that has already been mentioned or is clear from context. It is also frequently used as a dummy subject to talk about time, weather, or distance.

A preposition used to indicate that something is in a position above and supported by a surface. It is also used to indicate a specific day or date, or to show that a device is functioning.

A conjunction used to compare two things that are equal in some way. It is most commonly used in the pattern 'as + adjective/adverb + as' to show similarity.

Used to identify a specific person, thing, or idea that is physically close to the speaker or has just been mentioned. It can also refer to the present time or a situation that is currently happening.

A preposition used to show the method or means of doing something, or to identify the person or thing that performs an action. It frequently appears in passive sentences to indicate the agent or before modes of transport.

The word 'we' is a first-person plural pronoun used to refer to the speaker and one or more other people collectively. It is used as the subject of a sentence or clause.

A coordinating conjunction used to connect two or more possibilities or alternatives. it indicates that only one of the options is likely, required, or true.