Question

Which one of the following categories of animals, is correctly described with no single exception in it?

• A. All reptiles possess scales, have a three chambered heart and are cold blooded (poikilothermal)
• B. All bony fishes have four pairs of gills and an operculum on each side
• C. All sponges are marine and have collared cells
• D. All mammals are viviparous and possess diaphragm for breathing

Answer 1

Answer: (B)

All bony fishes have four pairs of gills and an operculum on each side

Answer 2

Heart is generally 3-chambered in reptiles but in crocodile, it is 4-chambered. Sponges are generally marine and have collared cells but few fresh water forms can also be seen like Spongilla. All mammals are viviparous (giving
birth to young ones) with an exception, Ornithorhynchus (platypus), which is oviparous (egg laying).