Hello There! ^_^
Your question: What is a darker contour line usually every fifth line..?
Your answer: An indes contour is a contour line that is usually in every fifth line.
Hope this helps!
One cardiac cycle is .8 seconds. A complete heartbeat is produced in one cardiac cycle. <span>The period of time that begins with contraction of the atria and ends with ventricular relaxation is known as the cardiac cycle. The period of contraction that the heart undergoes while it pumps blood into circulation is called systole.</span>
The answer is E because heart is circulatory and brain is part of your nervous system.
Answer:
Your digestive system absorbs water and nutrients from the food you eat. Your circulatory system carries oxygen, water, and nutrients to cells throughout your body. Wastes from the cells are eliminated by your respiratory system, your excretory system, and your skin.
Explanation:
