Question

Describe two ways evolution of organisms can have a harmful effect on humans.

Answer 1

Looks like the question is asking how evolution of a specific species affects humans negatively.
Think of co-evolution examples such as predator-prey and host-parasite relationships.
One example that comes to mind is the use of pesticides in agriculture. It has driven the evolution of resistant insects, requiring the use of harsher chemicals in greater quantity to kill them. This can have a harmful effect on agriculture and in turn affect humans negatively. Does that makes sense?