Ammm I ugly?? and guess my age

If the singular term ends in -us, the plural is usually formed by changing the ending to

What are three characteristics of positive self esteem?

Which of the following statements concerning cancer and mutations is correct? a: cancer can only occur with a mutation in a somatic cell. b: usually, multiple mutations are required in different genes to cause cancer. c: none of the other answer options is correct. d: cancer can only occur with a mutation in a germ cell. e: usually, a single mutation is all that is required to cause cancer.