The major function of the respiratory system is to: A. give the heart the energy it needs to circulate blood.
B. cleanse the body of toxins, poisons, and harmful chemicals.
C. maintain the digestive system of the body so that it can continue to operate.
D. provide oxygen to the body and eliminate carbon dioxide from the body.

When does a spring tide occur? question 9 options: they occur when the sun, moon, and earth are aligned. in spite of their name, these tides occur twice a year in the spring and fall. they occur on the date of the vernal equinox each year, no matter what stage the moon is in. this is why they are called spring tides. they occur when the sun, moon, and earth are at 45-degree angles from each other. this happens once every spring. they occur when the sun, moon, and earth are aligned. in spite of their name, these tides occur all year long.