Which of the following is true of flatworms and humans but not of ferns?
A. They are multicellular.
B. They are eukaryotic.
C. They are heterotrophic.
D. Their cells contain DNA.
The correct answer is option (C) they are heterotrophic.
Modes of nutrition in living organisms can be categorized into autotrophic and heterotrophic. Autotrophic nutrition is the process of synthesis of complex organic food substances by living organisms utilizing simple inorganic substances from the surroundings using light or inorganic chemical reactions. Heterotrophic nutrition is the process of obtaining complex organic food substances prepared by other organisms as they cannot synthesize their own food. It can be further classified into holozoic, parasitic, saprophytic and symbiotic.
Flatworms and humans exhibit heterotrophic mode of nutrition. Majority of the flatworms exhibit parasitic mode of heterotrophic nutrition. They obtain the food from the host like humans causing diseases in the them. Humans exhibit holozoic mode of heterotrophic nutrition. Complex food is taken in, digested into simpler substances, aborbed in the body and the undigested food is removed with the help of the digestive system. The stages of it include the ingestion, digestion, absorption, assimilation and egestion.
Ferns are the group of vascular plants that reproduce through the spores. The leaves or the fronds of the ferns are green and photosynthetic exhibiting autotrophic mode of nutrition.
