<u>Answer:</u>
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.
Okay so, the mitochondria are shaped perfectly to maximize their productivity. They are made of two membranes. The outer membrane covers the organelle and contains it like a skin. The inner membrane folds over many times and creates layered structures called cristae. The fluid contained in the mitochondria is called the matrix. The folding of the inner membrane increases the surface area inside the organelle. Since many of the chemical reactions happen on the inner membrane, the increased surface area creates more space for reactions to occur.
Hope that helps (:
The terrain of a biome has lots of different effects on its climate. For example, the sand of a desert absorbs heat and water, so it is constantly hot and it rarely rains.
I hope this helps.
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