| Intracellular digestion | Extracellular digestion |
| 1. The digestion of food occurs within the cell. | 1. The digestion occurs in the cavity of the alimentary canal. |
| 2. Digestive enzymes are secreted by the surrounding cytoplasm into the food vacuole. |
2. Digestive enzymes are secreted by special cells into the cavity of the alimentary canal. |
| 3. Digestive products are diffused into the cytoplasm. | 3. Digestive products diffuse across intestinal wall into various parts of bodies |
| 4. It is a less efficient method. | 4. It is a more efficient method of digestion. |
| 5. It mostly occurs in unicellular organisms. | 5. It mostly occurs in multicellular organisms. |
Prepare a list of some animals that are found parasitic on human beings.
Match the following:
| Column I | Column II |
| (a) Operculum | (i) Ctenophora |
| (b) Parapodia | (ii) Mollusca |
| (c) Scales | (iii) Porifera |
| (d) Comb plates | (iv) Reptilia |
| (e) Radula | (v) Annelida |
| (f) Hairs | (vi) Cyclostomata and Chondrichthyes |
| (g) Choanocytes | (vii) Mammalia |
| (h) Gill slits | (viii) Osteichthyes |
Segmentation in the body is first observed in which of the following:
(a) Platyhelminthes
(b) Aschelminthes
(c) Annelida
(d) Arthropoda
Could the number of eggs or young ones produced by an oviparous and viviparous mother be equal? Why?
What are the modifications that are observed in birds that help them fly?