Answer:
Everyone has different levels of melanin in them the more melanin you have the darker you are.
Explanation:
Finding out if an exercise is safe needs to determine the fitness level of the exercise and how much it takes to achieve the result of the exercise. The person performing the exercise needs to know their endurance level and if they are able to perform the exercise without injury or illness.
Answer:
The veins (blue) take oxygen-poor blood back to the heart.
Explanation: