Benign tumors normally remain confined to their original location.

• Correct - benign tumors don't spread, they remain localized.
Malignant tumors grow very rapidly, invading and damaging the surrounding normal tissues.

• Correct - malignant tumors are invasive and destructive.
Metastasis is the most feared property of malignant tumors.

• Correct - malignant cells spread to distant sites by metastasis, which is dangerous.
Proto-oncogene when activated under certain conditions, could lead to oncogenic transformation of cells.

• Correct - proto-oncogenes, when mutated or abnormally expressed, become oncogenes leading to cancer.