They are all relationships involving two animals where at least one animal benefits.
Parasitism- Where one organism benefits while the other is harmed. Examples-Mosquitos, ticks
Predation- Where one animal benefits and the other is harmed (or DEAD)
Example- Shark eats seal.
Commensalism- Where one organism benefits while the other is unaffected. Example-Bird riding on cows horns.
how are all these different?