Question

Where does Amoeba belong to
A) Protozoan
B) Porifera
C) Echinodermata
D) Molluscs

Answer 1

Hint: Amoeba often called amoeboid is the type of unicellular organism which can alter its shape, size with the help of pseudopods. Amoebas are either free-living in damp environments or parasites in nature. So we have to think of the class in which amoeba is a member.

Complete solution:
Protozoan - all protozoans are heterotrophs and live as predators or parasites. There are four types of protozoans- amoeboid protozoans, flagellated protozoans, ciliated protozoans, sporozoans.
Porifera - They are commonly known as sponges. They are generally marine and mostly asymmetrical. Mostly these are primitive multicellular animals and having a cellular level of the organization. They basically possess water transport or canal systems. Generally, water enters through minute pores (Ostia) in the body wall into the central cavity of sponges then follow spongocoel, from where it goes out through the pore osculum. This water transport system is helpful in food gathering, respiratory exchange, and removal of waste. Example: euspongia, spongilla.
Echinodermata- These animals are marine with organ system level of organization. As usual, adults are radially symmetrical but their larvae are bilaterally symmetrical. They are triploblastic and coelomate animals. Overall the digestive system is complete with the mouth on the lower side and anus on the upper side in case of echinoderms.
Mollusca - This is the second-largest animal phylum. Mollusca is terrestrial or aquatic having an organ system level of organization. Their body is covered by a calcareous shell and is unsegmented with a distinct head, muscular foot, and visceral hump.

Thus the option A is the correct answer.

Note:
Protozoans come in many different shapes and sizes. mostly Starting from amoeba which can change its shape to paramecium which has a fixed shape and also has a very complex structure. They live in a moist habitat like fresh-water, Marine environment, damp soil, etc. Some are parasitic which means they live in the body of another plant and animal including a human, where they cause disease, for example, Plasmodium that causes malaria.