Which animal performs respiration but does not possess a specialized respiratory organ?

Respiratory exchange in seeds occurs through

Choose the correct option by matching the organisms in Column-$I$ with their respective respiratory organs in Column-$II$.

Column-$I$	Column-$II$
$(p)$ Sponges	$(I)$ Through tracheal tubes
$(q)$ Insects	$(II)$ Through lungs
$(r)$ Molluscs	$(III)$ Vascularized gills
$(s)$ Reptiles	$(IV)$ Simple diffusion over their entire body surface
	$(V)$ By their moist cuticle

Find the correct sequence for $p-q-r-s$.

Which of the following does not have a specific respiratory organ,yet performs the process of respiration?

The diaphragm is absent in which of the following?

In which of the following is the skin an accessory respiratory organ?