Differentiate between active and passive immunisation giving one example of each.

Name and explain the interspecific interaction that exists between sea anemone and the clown fish.

(a) Which of the following animals undergo external fertilisation?

(i) Amphibians

(ii) Reptiles

(iii) Birds

(iv) Fish

(b) Mention one disadvantage of external fertilisation?

List four common warning signs of ‘drug and alcohol abuse’ among youth.

Explain the importance of growing microbes like Spirulina on a large scale.