The water vascular system of a sea star enables movement, digestion and respiration through the use of water to exert force on limbs known as tube feet. The vascular system is primarily water but also contains coelomocytes, protein and potassium salts.
Is caused by vibration, can travel through a vacum, and travels in longitudinal waves<span />
<span>Active and passive transport help to maintain homeostasis because they transport fluid/water/materials across the plasma lemma (cell membrane). All of these materials need to exist in certain ratios for the cell to function properly. </span>
<span>Plato first proposed that the planets followed perfect circular orbits around the Earth. Later, Heraclides (330 B.C.) developed the first Solar System model, placing the planets in order from the Earth it was is now called the geocentric solar system model.
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Can you please post each question separate in the comment section of this comment it’s to much to scroll through it’s easier if it’s separated thank you.