The diagnosis of cancer is based on which of the following?
$(1)$ Biopsy
$(2)$ Histopathological study of the tissue
$(3)$ Blood test
$(4)$ Bone marrow test

Which type of cancer is caused by tobacco smoke?

Which of the following diseases is expected to be completely curable in the next two decades?

Retroviruses are involved in cancer in humans because they ...............

Study the following sentences.
$I.$ The cells of malignant tumours divide erratically.
$II.$ They are malignant tumours of epithelial cells.
$III.$ They are malignant tumours of organs that originate from mesoderm.
$IV.$ These tumours are found in organs such as spleen and lymph nodes.
Which of the above are true for angiosarcoma?

. . . . . . converts normal cells into cancerous cells.