Do predators really kill only the old and sick prey? what evidence is there for this system

Many organs are involved in the processes of keeping the blood and the body clean. when poisonous or harmful substances are in the blood, they are absorbed by the and released in a less harmful form. when wastes are present in the blood, they are filtered out and removed from the body by the

Which beat describes the brain stem

What is the next step in muscle contraction after the actin changes shape? (apex)