An important characteristic that Hemichordates share with Chordates is:
1. | Ventral tubular nerve cord |
2. | Pharynx with gill slits |
3. | Pharynx without gill slits |
4. | Absence of notochord |
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
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 |