The answer is the letter B. Electrical signals.
*Our brain and body communicates with each other by sending messages in the form of electrical signals.
Answer: Hairlessness and Glands
explanation:Another notable similarity between the two groups is minimal hair. Both hippos and whales possess barely any hair on their bodies. They do not have sweat glands, either. These are both characteristics that can assist them in their aquatic lifestyles.
Answer: Rivers
Explanation: Runoff from cars and other pollutants usually flow off of roads into rivers or streams that usually lead into bigger bodies of water such as oceans.