Which among these is the correct combination of aquatic mammals?
1. Dolphin, Seals, Trygon
2. Whales, Dolphin, Seals
3. Trygon, Whales, Seals
4. Seals, Dolphin, Sharks
Choose the correct statement.
| 1. | All mammals are viviparous |
| 2. | All cyclostomes do not possess jaws and paired fins |
| 3. | All reptiles have a three-chambered heart |
| 4. | All Pisces have gills covered by an operculum |
In the case of Poriferans, the spongocoel is lined with flagellated cells called:
1. Oscula
2. Choanocytes
3. Mesenchymal cells
4. Ostia
Which of the following characteristic features always hold true for the corresponding group of animals?
| (a) | Viviparous | (1) | Mammalia |
| (b) | Possess a mouth with an upper and a lower jaw | (2) | Chordata |
| (c) | 3- chambered heart with one incompletely divided ventricle | (3) | Reptilia |
| (d) | Cartilaginous - Endoskeleton | (4) | Chondrichthyes |
1. a
2. b
3. c
4. d
A jawless fish, which lays eggs in freshwater and whose ammocoetes larvae after metamorphosis return to the ocean is?
1. Eptratretus
2. Myxine
3. Neomyxine
4. Petromyzon
Metagenesis refers to?
| 1. | The presence of different morphic forms |
| 2. | Alternation of generation between asexual and sexual phases of an organism |
| 3. | Occurrence of a drastic change in the form during post-embryonic development |
| 4. | Presence of a segmented body and parthenogenic mode of reproduction |