Question

All animals mostly fall in the category of _______________.
(a) Heterotrophs
(b) Autotrophs
(c) Decomposers
(d) Primary consumers

Answer 1

Hint The mode of nutrition of an organism depends on the type of food they eat. Every organism has different complexity of body organization which depends on their role in the environment and phylogenetic relationship.

Complete Answer:
All animals mostly fall in the category of heterotrophs because animals cannot prepare their food and they obtain their food directly or indirectly from other organisms. Animals are mainly divided into herbivorous animals, carnivorous animals, and omnivorous animals. Herbivorous animals mainly feed on the plant, carnivorous animals are flesh-eating animals that feed on other animals and omnivorous animals feed on both plants and animals.

Additional information:
The heterotrophic mode of nutrition is divided into the ingestive and absorptive mode of nutrition. In the ingestive mode of nutrition higher animals and protozoa ingest their food in solid form. In the absorptive mode of nutrition, animals obtain their food in liquid form if organisms feed on the dead organic matter they are considered as saprozoic.
Autotrophic mode of nutrition shown by those organisms who synthesize their organic food from inorganic raw materials obtained from the environment. Autotrophic mode of nutrition is divided into photoautotrophs and chemoautotrophs. Photoautotrophic organisms obtain their food by the process of photosynthesis in which solar energy is utilized to convert inorganic raw material to organic food. Photoautotrophic mode of nutrition is found in that organism in which photosynthetic pigments are present, they all are producers. The chemoautotrophic organisms are those organisms which obtain their energy by conducting chemical reaction to prepare organic food. These organisms lack photosynthetic pigment hence they didn't show photosynthesis.
Primary consumers are mostly herbivorous animals that feed mainly on lower to higher plants.

So, the correct answer is Heterotrophs.

Note: Insectivorous plants show both heterotrophic and autotrophic modes of nutrition. They perform photosynthesis to obtain their food but to fulfill nitrogen demand they trap insects because the insectivorous plant grows in nitrogen-deficient soil.