I think c is the correct answer
Phosphorous: Also known as phosphoric acid and phosphate, phosphorous, which is in cola and many processed foods, can interfere with calcium absorption.
Insoluble fiber: This type of fiber, such as the kind in wheat bran, reduces calcium absorption
Foods with high levels of oxalic acid include spinach, collard greens, sweet potatoes, rhubarb, and beans and this will interfere with calcium absorption.
A vast network of nerves sends electrical signals to and from other cells, glands, and muscles all over your body. These nerves receive information from the world around you. Then the nerves interpret the information and control your response.
A flatworm does not have a body cavity.