Question

Choose the correct statement with respect to unicellular organisms:
A. In unicellular organisms, tissues work in coordination to perform different functions.
B. Unicellular organisms do not require food
C. Unicellular organisms respire and reproduction
D. All unicellular organisms move by Cilia

Answer 1

Unicellular is a single celled organism whereas multicellular organisms consist of more than one cell. All multicellular organisms originated from unicellular organisms. Through the process of evolution.

Complete answer:
Unicellular organisms consist of a single cell. This single cell performs the all vital functions of an organism. It includes respiration, reproduction , energy synthesis from food, locomotion, perception. Unicellular organisms are classified into two different categories prokaryotes and eukaryotes. This classification is based on the presence of nucleus and nuclear membrane. Prokaryotes do not have nucleus and nuclear membrane. Most of the prokaryotic organisms are unicellular whereas some of the eukaryotes are multicellular.

Let us discuss the difference between unicellular and multicellular organisms.
- Unicellular organisms lack the tissue and organ system and it also lacks the membrane bound organelles.
- Multicellular organisms have well developed membrane bound organelles and there is presence of tissue and organ system.
- Multicellular organisms are composed of many single cells. They have well developed and coordinated tissue systems to perform the different functions of the organism.
- Multicellular organisms have well-developed locomotive systems. Unicellular organisms move by the process of pseudopodia, cilia, flagella. All the living organisms require food and undergo the process of respiration and reproduction.
- Multicellular organisms have different systems for every specific function of the organism.
- Unicellular organisms do not breathe but uptake the oxygen by the process of diffusion. Since they are too small and they do not have the respiratory organs.
- Unicellular organisms take the food by the process of engulfing.
- Unicellular organisms reproduce by the process of binary fission virus multicellular organisms reproduce by sexual or asexual methods.

Hence, the correct answer is option (C).

Note: Generally most of the unicellular organisms are microscopic in nature. Some of the unicellular organisms are visible to the naked eye. The algae Caulerpa is the largest unicellular organism. Mostly , the unicellular organisms are present in the Water bodies.