Question

Some invertebrates combine morphological simplicity with features of great structural or biochemical complexity. Select all correct examples of this statement.
Select all that apply.

Sponges lack true tissues but have more variation in cell type than animals in any other phylum.
Trematodes are acoelomates that have effective defenses against attack by their hosts' immune system.
Cnidarians are diploblasts that produce complex, capsule-like organelles.

Answer 1

The correct answers are:

Trematodes are acoelomates that have effective defenses against attack by their hosts' immune system.

Trematodes are flatworms, internal parasites known as flukes. Their life cycle is complex: they sexually reproduce in vertebrates and asexual reproduce in mollusks (mostly snail). The body of flukes is covered with tough tegument that defends them form digestive enzymes of host’s intestine.

Cnidarians are diploblasts that produce complex, capsule-like organelles.

Cnidaria are water organisms with simple structure: two layers of epithelium and a jelly substance between them. The cells of Cnidaria-cnidocytes contain capsule with venom substance in it with protective role.