21. All the following are differences between arteries and veins except
arteries are thick and veins are thin
O arteries do not have valves and veins have valves
arteries connect to capillaries and veins do not connect to capillaries
arteries carry blood away from the heart and veins carry blood back to the heart
22. All the following are the 3 major parts of the cardiovascular system
VA

Arteries connect to capillaries and veins don't connect to capillaries

Explanation:

Actually both are connected by capillaries

one part of the electromagnetic spectrum that arrives on earth as solar radiation from the sun is the visible spectrum. wavelengths of the visible spectrum combine to form what we refer to as

answer - d) ultraviolet radiation.

violet /   380–450 nm / 668–789 thz

violet is number 1 in the chart of visible light.