Which of the following statements is true?

a) cool air is less dense than warm air.
b) sound does not require a medium for travel.
c) magnetism is caused by the spinning motion of electrons.
d) electricity flows from positive to negative areas.

Magnetism is caused by the spinning motion of electrons. is true :)

Explanation:

the correct answer is: d. the saltine and pretzel are made of flour, yeast, and baking soda, and salt. the pecan contains no flour but it does contain fats. the pecan is a nut that can be consumed as a healthy snack. first of all, pecans are a source of fat (monounsaturated fat), but they provide less fat than some other nuts. pecans are a rich source of dietary fiber, manganese magnesium, phosphorus, thiamin, vitamin e…

answer: although many types of viruses can cause a common cold, rhinoviruses are the most common culprit. a cold virus enters your body through your mouth, eyes or nose. the virus can spread through droplets in the air when someone who is sick coughs, sneezes or talks. theres your answer

explanation: