Question

Exclusive holozoic nutrition is seen in
A) Housefly
B) Spider
C) Man
D) Shark

Answer 1

Holozoic nutrition is a kind of heterotrophic nutrition. It involves ingestion of the whole food. Digestion, absorption and assimilation of it takes place inside the organism. The undigested food is eliminated from the body by the process of egestion.

Complete answer:
The food is the most important thing that an organism needs to obtain energy. The food can be in the form of solid as well as liquid. Some organisms obtain the nutrients from the other sources like parasites, saprotrophs etc. Some organisms undergo holozoic nutrition in which they ingest the solid or liquid food, digest, absorb assimilate and excrete inside the body of the organism. The example of the organism that undergo holozoic nutrition is man. They take in food through mouth, digest the food in the moth, stomach and intestine, absorb and assimilate in the intestine and excrete the undigested food through the anus. The digestive enzymes help in breakdown of food.

Housefly and spider: The housefly and spider undergo saprozoic nutrition in which they secrete digestive enzymes on their food outside their body and take in the partially digested food. This mode of nutrition is same as that in bacteria and fungi.

Shark: The sharks do not undergo exclusive holozoic nutrition. The unwanted food is vomited from the mouth and also the stomach moves in to eliminate the unwanted food. So the mode of nutrition is not exclusively holozoic as they lack egestion system.

Therefore the correct answer is option ‘C’.

Note: The digestion of food is brought about by the digestive enzymes. These enzymes break the food into simpler substances that can be easily utilised by the organism. In human beings the fastest source of energy is the glucose.