Question

Match the type of cells given in column 1 with organisms given in column 2. Choose the appropriate combination of the options.

Column1	Column 2
Flame cells	i) Sponges
Collar cells	ii) Hydra
Stinging cells	iii) Planaria

A) A - (iii), B - (i), C - (ii)
B) A - (iii), B - (ii), C - (i)
C) A - (i), B - (ii), C - (iii)
D) A - (ii), B - (iii), C - (i)

Answer 1

Hint:Let us first have a brief idea about sponges, hydra and planaria. Sponges are multicellular organisms that belong to phylum Porifera. They have a porous body with channels for the circulation of water through them. Hydra is a freshwater organism that belongs to phylum Cnidaria. They are thin, usually translucent tube-like structures with an oral opening surrounded by tentacles. Planaria is a free living flatworm that belongs to the phylum Platyhelminthis. Their elongated body is soft, ciliated and leaf shaped.

Complete Answer:
Freshwater invertebrates like planaria, flatworms, rotifers etc have specialized excretory cells called flame cells. They resemble kidneys in their functionality. Collar cells are the flagellated cells that line the inner chambers of sponges. Collar cells are also known as choanocytes.They help in circulation, excretion, respiration and nutrition. Stinging cells are the characteristic features of cnidarians. They are found in hydra, sea anemone, jellyfish, and corals which help in catching prey.

Therefore the correct option is (A) A - (iii), B - (i), C - (ii).

Note: Remember that sponges are sessile animals which grow in one spot like plants. Collar cells are also known as choanocytes. Planaria has the ability to regenerate. When divided into two pieces, each piece is developed into a new individual. Hydra undergoes asexual reproduction just like plants through budding.