Biological Classification, on the exam screen.

Whittaker's five kingdom classification was based on cell structure (Statement I), body organisation (Statement II), mode of nutrition, reproduction (Statement IV) and phylogenetic relationships (Statement V). Presence of a flagellum (Statement III) was not one of the main criteria, so the correct set is I, II, IV and V.

Aptenodytes is the genus of penguins, flightless birds whose forelimbs are modified into paddle-like flippers used for swimming.
Struthio (ostrich) is flightless but its reduced wings are used for balance while running, not swimming, while Neophron (vulture) and Psittacula (parakeet) are flying birds.
Hence Aptenodytes.

In a lichen the algal partner (the phycobiont) photosynthesises and supplies food, while the fungal partner (the mycobiont) provides shelter, anchorage and absorbs mineral nutrients and water. Lichens are highly sensitive to pollution, which is why they are used as air-quality indicators. NCERT Class 11, Biological Classification.

Prions are abnormally folded PROTEIN particles with no nucleic acid at all. They act as templates that force the normal cellular protein into the same misfolded shape, producing spongiform degeneration of the brain. Bovine spongiform encephalopathy in cattle and its human counterpart, Creutzfeldt-Jakob disease, are both prion diseases. NCERT Class 11, Biological Classification.

Bacteria are classified by shape into four basic forms: spherical cocci (P-II), rod-shaped bacilli (Q-IV), comma-shaped vibrio (R-I) and spiral spirilla (S-III). The names are worth learning together because each is simply the Latin word for the shape. NCERT Class 11, Biological Classification.

Fungi belong to Kingdom Fungi and are EUKARYOTES - they possess a true membrane-bound nucleus, mitochondria and other organelles. The other three are all prokaryotic members of Kingdom Monera: bacteria, cyanobacteria (blue-green algae) and the wall-less Mycoplasma. NCERT Class 11, Biological Classification.

Sexual reproduction in fungi runs through three named steps in sequence. Plasmogamy is the fusion of the two protoplasts (P-II), karyogamy is the subsequent fusion of the two nuclei (Q-III), and meiosis in the resulting diploid zygote restores the haploid condition and generates spores (R-I). In many fungi plasmogamy and karyogamy are separated by a long dikaryotic phase, which is why they are named as distinct events. NCERT Class 11, Biological Classification.

Viroids are infectious agents composed of short strands of naked RNA without a protein coat. Chapter: Biological Classification.