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Question:

Which of the following statements are correct?

All sponges are marine and shows presence of collared cells.

All mammals are viviparous and possess diaphragm for breathing.

All bony fishes have eight gills along with operculum on each side.

All reptiles possess scales, have a three-chambered heart and are cold blood (poikilothermal).

Solution:

All bony fishes have four pairs of gills and an operculum on each side. Sponges are mostly marine, but there are a few freshwater species as well. Not all mammals are viviparous; monotremes are oviparous mammals. The only crocodile is an exception in reptiles which possess a 4-chambered heart. Thus, the correct answer is option A.