BIOLOGY 2 Marks Questions

In case of fishes, of class-Osteichthyes, i.e., Exocoetus (flying, fish), Hippocampus (sea horse), Labeo (rohu) and Clarias (magur), etc., air bladders are present which regulate the buoyancy and help these animals in swimming in deeper layers of water.

Water vascular system is a characteristic feature of the phylum Echinodermata. It consists of an array of radiating channels, tube feet, and madreporite. The water vascular system helps in locomotion, food capturing, and respiration.

The characteristic features of the phylum, Chordata, include the presence of a notochord and paired pharyngeal gill slits. In sub-phylum Vertebrata, the notochord present in embryos gets replaced by a cartilaginous or bony vertebral column in adults. Thus, it can be said that all vertebrates are chordates but all chordates are not vertebrates.

1. Anal styles in male.

1. Parotids.

3. Convergent evolution.

4. Linnaeus.

1. Echinoidea.

1. Two

Explanation:
All vertebrates have a muscular chambered heart.
Fishes have a two chambered heart with a single atrium and a ventricle.
In fishes, the heart pumps out deoxygenated blood which is oxygenated by the gills and supplied to the body parts from where deoxygenated blood is returned to the heart (single circulation).

3. Have gill slits at some stage.

3. Coelenterata and Echinodermata.

2. Endothermic.

2. True placentation.

4. Snake.

4. Mature proglottids contain both male and female organs

3. Ecdysone.

4. Moist skin.

2. Contractile vacuole.

3. Sand fly.

2. Forelimbs are modified for flight in Bats.

2. Both.

2. Flame cells.

2. Nematocysts.

3. Pseudocoelom.

1. A is true but R is false.

3. Benthos/ sedentary.

3. Fasciola is a pseudocoelomate animal.

Explanation:
The statement, Fasciola is a pseudocoelomate animals, is incorrect as it does not possess body cavity hence, it is an acoelomate. Mesoglea is an undifferentiated layer and is a characteristic of diploblastic and triploblastic animals present along with ectoderm and endoderm. Symmetry in which the body can be divided into two equal identical halves from any plane passing through the central axis. as shown by Asterias, is called radial symmetry Taenia is a triploblastic animal, it possesses three germinal layers, i.e., ectoderm, endoderm and mesoderm.

1. Presence of skull.

1. Tuataras.

4. Flying fish.

4. Frog.

2. Muscular diaphragm between thorax and abdomen.

4. Mosquito larvae in permanent waters.

1. Presence of notochord.

4. Cephalopoda.

3. Ten pairs of cranial nerves.

3. Dorsal surface.

2. Muscular diaphragm.

2. Mesozoic.

1. Oncosphere.

2. Rhabditiform.

3. Flightless birds.

2. Starfish.

4. Mesoderm on both sides.

3. Rostellar hooks are absent.

2. They make the soil porous, leave their castings and take organic debris in the soil.

3. Echinodermata.

1. Crocodile.

2. Two pairs of antenna.

1. Spicules.