Viruses are obligate parasites because they cannot carry out metabolic processes or reproduce independently. They rely on the cellular machinery of a host organism to replicate and propagate. Viruses are essentially genetic material (either DNA or RNA) enclosed in a protein coat, which is called a capsid (option D is incorrect). Option A is incorrect because viruses lack their own metabolic systems, and option B is incorrect because not all viruses contain both RNA and DNA; they can have one or the other as their genetic material.
So, the correct option is (C): Viruses are obligate parasites
| List I | List II | ||
| A | Typhoid | I | Fungus |
| B | Leishmaniasis | II | Nematode |
| C | Ringworm | III | Protozoa |
| D | Filariasis | IV | Bacteria |
Each of the following characteristics represents a Kingdom proposed by Whittaker. Arrange the following in increasing order of complexity of body organization.
A. Multicellular heterotrophs with cell wall made of chitin.
B. Heterotrophs with tissue/organ/organ system level of body organization.
C. Prokaryotes with cell wall made of polysaccharides and amino acids.
D. Eukaryotic autotrophs with tissue/organ level of body organization.
E. Eukaryotes with cellular body organization.
Choose the correct answer from the options given below:
Match Column - I with Column - II.
| List - I | List - II | ||
| (a) | Metamerism | (I) | Coelenterata |
| (b) | Canal system | (II) | Ctenophora |
| (c) | Comb plates | (III) | Annelida |
| (d) | Cnidoblasts | (IV) | Porifera |
Choose the correct answer from the options given below.