Conserve (verb)

1. To keep or preserve (something) from harm or injury; protect.
2. To use or manage (natural resources) wisely; preserve.
3. To keep (something) in its original state; preserve.
4. To keep (something) from decaying or being used up; preserve.

Origin:

From latin conservare "to keep, preserve".

Examples:

1. We must conserve our natural resources for future generations.
2. Conserve energy by turning off lights when leaving a room.
3. The government is taking steps to conserve endangered species.
4. Conserve the historical monuments.
5. Conserve the water resources.