NATIONAL QUARTERFINAL STAGE 2026
Achimota School: 55
Adisadel College: 28
Boa Amponsem SHS: 23
QUESTION
Red tide is caused by what type of organism?
ANSWER: Dinoflagellate.
EXPLANATION
Red tides are harmful algal blooms caused by the explosive multiplication of dinoflagellates, single-celled protists that often contain reddish-brown photosynthetic pigments; their bloom can discolor coastal water and release toxins harmful to marine life and humans.
PRACTICE QUESTIONS
1. To which kingdom do dinoflagellates belong?
ANSWER: Protista.
2. How do dinoflagellates move?
ANSWER: By two flagella.
3. What is an algal bloom?
ANSWER: A rapid increase in the population of algae in water.
4. State one effect of a red tide on marine life.
ANSWER: It can kill fish and other marine animals through toxins.
5. Why do red tides appear reddish-brown?
ANSWER: The dinoflagellates contain reddish pigments.
6. Name one condition that triggers red tides.
ANSWER: Warm water rich in nutrients.
7. Are most dinoflagellates photosynthetic?
ANSWER: Yes.
8. What is bioluminescence?
ANSWER: The production of light by living organisms, shown by some dinoflagellates.
9. Why do shellfish become poisonous during a red tide?
ANSWER: They filter the dinoflagellates and store the toxins in their bodies.
10. What forms the armour-like covering of many dinoflagellates?
ANSWER: Cellulose plates.
11. Name a disease people can get from eating shellfish poisoned by dinoflagellates.
ANSWER: Paralytic shellfish poisoning.
12. What human activity can lead to nutrient enrichment of coastal waters?
ANSWER: Runoff of fertilisers and sewage.