Compare and contrast the adaptations of free-living flatworms and parasitic flatworms

Free-living flatworms have developed a nervous system which helps them to sense the food. They have a head at one end of the body and each side of the head has sensory cells. These cells help them to sense chemicals and other movements around them.

While Parasitic flatworms don't have any nervous or digestive system as they live on the food digested by the host. They have special hooks attached to their head which help them to attach a host. They have developed some covering called 'teguments' which protect them from digestive liquids.

explanation:

the universal gravitation equation. since the gravitational force is directly proportional to the mass of both interacting objects, more massive objects will attract each other with a greater gravitational force. if the mass of one of the objects is doubled, then the force of gravity between them is doubled.