WELL if a person wants to know about his/her surrounding, what is it made up of, how our body or other animal's body function, evolution of organisms, etc.
Also to become a biologist, doctor!!
No, definitely not. To be a surgeon, you not only need biology, but you also need physics, inorganic chemistry, organic chemistry, and a high level mathematics, traditionally calculus.
Biology is the study of all living things, from microscopic organisms up to the largest lifeforms we know about. It's important to know how living things work, because humans are living things....