Question

Select the option that correctly matches the characteristic features with the group of three animals.
a. Skeleton of spicules – Syon, Adamsia, Spongilla
b. Excretion by flame cells – Taenia, Fasciola, Ancylostoma
c. Mouth contains radula – Dentalium, Octopus, Ophiura
d. Jointed appendages – Limulus, Apis, Laccifer

Answer 1

We know animals are multicellular eukaryotes with common features such as sensory organs and mobility. Nevertheless, every species in the animal kingdom has characteristics that are unique to them. These features are specific to their ecosystem and important for their survival and everyday activities.

Complete answer:

Option A: Skeleton of spicules –
This type of skeleton belongs to sponges of phylum Porifera. The sponges are multicellular organisms with pores in their body through which water circulates. The mesh like spicule fibers protect them from predators and provide structural support. Syon and Spongilla are sponges while Adamsia belongs to coelenterate.

Option B: Excretion by flame cells –
These cells are found in platyhelminthes, which are simple freshwater invertebrates, and a bundle of flame cells is called protonephridia. They remove waste from their body which is similar to the function performed by kidneys in humans. They also regulate osmotic pressure and ionic balance. Taenia and fasciola possess flame cells but Ancylostoma belongs to aschelminth.

Option C: Mouth containing radula –
Radula can be seen in mollusks, which is an anatomical structure used to scrape and cut food before it enters the oesophagus. The morphology of radula varies among mollusks and is dependent on the type of food abundant to them. In the options given, Dentalium and octopus are mollusks while ophiura is an echinoderm.

Option D: Jointed appendages –
This is a characteristic feature of arthropods having segmented bodies with jointed limbs. They help in locomotion and provide protection to the arthropods from desiccation and support against gravity. All the three options mentioned belong to arthropods.

Hence, the correct answer is option (D).

Note: The spicules are found to act like optic fibers in certain deep-sea sponges. They can trap and transport light in the dark conditions and are also a source of light to the algae underwater.