Which of the following substances found in tobacco smoke stimulates the brain?
a. acetone
b. toluene
c. nicotine
d. ammonia

The substance that is found in the tobacco smoke that stimulate the brain is the nicotine. Nicotine is a highly addictive drug that acts through the brain and to the rest of the body parts. Other than nicotine other harmful substances can also lead to various health effects such as lung cancer, emphysema, etc.

The answer is c. nicotine

3/4 divided by 1/4 = 3

Step-by-step explanation:

When we divide two fractions, such as 3/4 ÷ 1/4, we flip the second fraction and then we simply multiply the numerators with each other and the denominator with each other.

We also simplify the answers to fraction problems whenever possible.