Q5. Why may ‘a photosynthetic protistan’ to one biologist be ‘a plant’ to another?
Because the boundaries of Kingdom Protista are not well defined (NCERT page 14).
Q6. How are the two flagella of a dinoflagellate arranged?
One lies longitudinally and the other transversely, in a furrow between the wall plates (NCERT page 15).
Q7. How does a ciliated protozoan feed?
The coordinated movement of rows of cilia steers water laden with food into its gullet, a cavity that opens to the outside of the cell surface (NCERT page 16).
Q8. What do slime moulds form under suitable conditions, and under unfavourable ones?
Under suitable conditions, an aggregation called a plasmodium, which may spread over several feet; under unfavourable conditions, fruiting bodies bearing spores at their tips (NCERT page 15).
Q9. Assertion: diatoms can leave large deposits in their habitats. Reason: their silica-rich walls can persist after the cells die. Are both true, and does the reason explain the assertion?
Both are true, and persistence of the walls helps explain accumulation as diatomaceous earth. NCERT calls the walls “indestructible” (page 14), but this is not literal: silica dissolution also occurs, and deposition depends on conditions.
Q10. Which amoeboid protozoan is a parasite, and what covers the marine amoeboid forms?
Entamoeba is a parasite; marine forms have silica shells on their surface (NCERT page 16).
Q11. How do euglenoids feed when deprived of sunlight?
NCERT describes heterotrophy by predation on smaller organisms (page 15). Do not make that mechanism universal: some euglenoids grow heterotrophically by taking up dissolved organic nutrients, as explained above.
Q12. Name the protist group with an infectious spore-like stage, and its most notorious member.
Sporozoans; Plasmodium, the malarial parasite (NCERT page 16).