(a) A number which has only two factors is called a prime number.
By definition of prime number, a number is said to be prime if it has only 2 factors 1 and the number itself.
(b) A number which has more than two factors is called a composite number.
By definition of a composite number, a number is said to be composite if it has more than 2 factors.
(c) 1 is neither prime number nor composite number.
Since 1 only has the factor number, hence is neither prime nor a composite number.
(d) The smallest prime number is 2.
1 is neither prime nor composite so 2 is the smallest prime number.
(e) The smallest composite number is 4.
In contrary to 2 and 3, which are prime numbers, 1 is neither prime nor composite. So 4 is the smallest composite number having factors as 1, 2, and 4.
(f) The smallest even number is 2.
2 is both even and prime. So 2 is the only even prime number.