Answer the following question given this paragraph: 

Cancer of the testes is most common in males aged 15 to 35. It occurs when cells in the testes grow out of control and form a tumor. If found early, cancer of the testes usually can be cured with surgery.


Q: What forms when cells start to grow out of control?

 Choices:

- fat

- moles

- inflammation

- tumor

A:
tumor
