The answer to the question is enzyme linked receptor.
Answer: B. by toxic chemicals (in smoke) or radiation that can damage the DNA in cells.
Explanation:
The carcinogens presents in cigerates covalently bind to DNA and form DNA adducts which results into miscoding (e.g., insertion of the wrong base) during replication of DNA and this genetic mutation causes uncontrolled cellular growth which causes cancer.
Ionising radiation including X-rays, radioactive particles, and gamma rays,can cause cancer by damaging DNA. high-energy radiation damages DNA and cause genetic mutation same as cigerates and causes cancer.
Both toxic chemicals (in smoke) or radiation damages DNA inthe cells which leads to cancer.
Hence, the correct option is B.
