Answer:
1. Individuals in a species vary in characteristics because of differences in their genes.
Individuals will be born with various characteristics due to their genes for instance some people are short and other are tall.
2. Individuals have to compete when resources (such as food) are limited.
Resources are generally limited so individuals would have to compete t get those resources and survive.
3. Individuals with variations that help them get more of the resources are more likely to survive.
Some of the characteristics that these individuals have which are different will give them an edge and enable them to get more resources and thus survive.
4. Individuals that survive can pass their genetic variations on to their offspring.
The individuals that survive will now have offspring and will pass on their genes to their offspring which give give them the same edge their parents had.
5. Over time, there are more individuals with the variations that are well adapted to the environment.
Eventually there will be more of those offspring that can adapt as opposed to those who couldn't and keep dying out.