Question

Animals belonging to platyhelminthes are also called flat worms because
A.Their head is flat.
B.They have dorsoventrally compressed bodies.
C.They creep over the surface.
D.The alimentary canal is flattened.

Answer 1

Hint: Platyhelminthes are dorsoventrally straightened from head to tail. They are dorso-ventrally smoothed. Flatworms / Platyhelminthes have three germ layers exoderm, endoderm, and mesoderm however do not have a body cavity or coelom.

Complete answer:
Platyhelminthes are normally known as flatworms or tapeworms. They are a gathering of delicate bodied invertebrate creatures. Truly, there are around 20,000 types of these creatures. A couple of these live as parasites on people and different creatures. Besides, it is a direct result of this parasitic nature that they do raise some measure of troubles for the host creature. A couple of animal varieties having a place with this phylum can be a significant reason for specific ailments. For instance, Schistosomiasis, or bilharzia or bilharziasis, is an infection brought about by these parasitic flatworms. They have a place with the family Schistosomatidae.

The most distinctive component of these spineless creatures is their level body. As the body doesn't have any depression, they are level. The body is additionally not divided and they don't have particular frameworks. Around a lot of the flatworms are parasitic in nature, while a couple of freestyle flatworms are additionally present. The free-living structures are scavengers or predators. The parasitic species feed on the tissues of the host life form in which they live.

The creatures in this phylum have a different reach in size. Some are minuscule, while a couple go up to two feet in length. They are likewise bisexuals, which imply that both the genders are available in a similar life form.

So, the correct answer is option B.

Note: Platyhelminthes are a gathering of spineless creatures that are likewise called as flatworms on the grounds that their bodies are dorsoventrally flattened. So they seem like strips like animals. They are generally simple, bilateral, unsegmented and delicate bodied invertebrates.