Both marijuana and tobacco smoke contain ______ which are substances that cause cancer.

A: Delta-9-tetrahydrocannabinol(THC)
B: Thiamine and dextrose
C: Enzymes
D: Carcinogens

D: Carcinogens

D: Carcinogens

The correct answer is D: Carcinogens.

To arrive at this answer, let's break down the question and examine each option.

A: Delta-9-tetrahydrocannabinol (THC) - THC is the main psychoactive compound found in marijuana. While it has various effects on the body, it is not directly responsible for causing cancer.

B: Thiamine and dextrose - Thiamine is a vitamin and dextrose is a form of glucose. Neither of these substances is known to be carcinogenic.

C: Enzymes - Enzymes are proteins that facilitate chemical reactions in the body. They do not inherently have carcinogenic properties.

D: Carcinogens - Carcinogens are substances that can cause cancer. Both marijuana and tobacco smoke contain various carcinogens, which are known to be harmful to human health.

Therefore, the correct answer is D: Carcinogens. Both marijuana and tobacco smoke have been linked to an increased risk of developing cancer due to the presence of these harmful substances.