Flatworms will be best suited to terrestrial environment.
Explanation:
A 2 reasons flatworms live on land
The flatworms develop muscle tissues due to the mesoderm layer can easily move on the land hence suited for terrestrial life.
Flatworms do not have the digestive system they rely on food digested by the host.
They have sensory cells in their nervous system which help them recognize food.
B. 2 reasons why nematode don't live much on land
The roundworms or nematodes are the heterotrophs and often co-habitat as a parasite.
Nematodes feed on bacteria, fungi and protozoans from the soil or freshwater.
They require large internal pressure to move as no cilia or flagella are found in them.
