Answer:
reproduction
Explanation:
A living thing is characterized by its ability to perform certain functions including growth, irritability, reproduction, respiration etc. Of all these characteristics, REPRODUCTION is key to the survival of an organism's species.
An individual organism will definitely survive without reproducing i.e it will continue living and undergoing its day-to-day activities. However, in order to ensure that its species amongst others survive and not be EXTINCT, it has to reproduce. Reproduction gives rise to more of the same species of organism to form a POPULATION.
