Have a pseudocoelom and are the simplest animals that have a complete digestive tract.

Nematodes have a pseudocoelom and are the simplest animals that have a complete digestive tract.

Nematodes also known as roundworms are animals well adapted to variety of environments, meaning that are ubiquitous. Nematodes are small, bilaterally symmetric with ornamented ring body structures. Their body is covered with cuticle that works with the muscles beneath it to create a hydroskeleton. There are free-living species and parasitic species of Nematoda.  

1.the evidene of the reaction

2.yes

3.yes