How does reproduction help in providing stability to the population of a species?

Hint: Reproduction is a process of producing new individuals of the same species from existing organisms. This process maintains the flow of species and helps in studying evolution.

Complete answer:
Multicellular organisms have special cells called gametes for reproduction which contain only half the number of chromosomes. So when gametes from two different parents combine during reproduction, it results in a new individual, which contains DNA (the genetic material passed from parents) and re-established a number of chromosomes. This process is done by many species to produce their off-spring as it is the only means to ensure the continuity of a species.
Reproduction is mandatory to provide stability and balance on the planet. Birth and death are standard events that balance the universe. We need to maintain the ratio of rate of birth equal to rate of death. Organisms usually produce huge numbers of new individuals out of which several die and only some survive. These surviving organisms replace the older population (who might have died naturally) and thus maintain a balance. Thereby ensuring the survival of the species. If either one of this phenomena stops occurring the balance will be lost. If species just keep dying and reproduction doesn’t occur, the planet will no longer have living organisms.
DNA replication is responsible for the variations among organisms that allow an organism to survive in a particular niche. Genetic variations are also the result of gene mutations and gene flow. Reproduction assists to generate variation among the genome (it contains all of the genetic material). As reproduction occurs with two parents it introduces some variations in the individual. The variations introduced in some individual organisms may help them to survive in new environmental conditions such as excessive heat or cold or shortage of water, etc. whereas other members of the species might die. The introduction of variations during reproduction provides stability to the populations by preventing some of their individuals from getting wiped out.

Note:
 The molecule of a DNA (deoxyribonucleic acid) which contains a part or all of the genetic material of an organism is called Chromosome. Humans have 23 pairs of chromosomes (or 46 chromosomes) present in a human body. The 23rd pair determines the sex (gender) of the human. Organisms that have more than one cell i.e a tissue, organ or organism that is made up of many cells are known as multicellular organisms. Animals, fungi, algae, plants are all multicellular organisms.