The amount of fluid displaced is directly related (via Archimedes' principle) to its volume. In the case of an object that sinks (is totally submerged), the volume of the object is displaced. In the case of an object that floats, the amount of fluid displaced will be equal in weight to the displacing object.
Animals gain energy from the food they eat. Some animals eat plants while others eat other animals. This is passing of energy from the sun to plants to animal to other animals is called a food chain
A solid is defined as substance with a set volume and form. A liquid is defined as substance with a set volume but no fixed form. A gas is substance that does not have a definite volume or shape. Plasma, like a gas, has no set volume or shape.