Which of the following animals was given as a wedding gift in Japan, as symbolizing the idea, ‘till death do us part’?
A. Hyalonema
B. Euplectella
C. Sycon
D. Euspongia

Hint: Venus flower basket or glass sponge is used as a symbol of eternal love or undying love in some Asian countries such as Japan and given as a marriage gift. It is a marine sponge which is mainly found in the deep waters of the Pacific Ocean.

Complete answer:
Sponges, the member of phylum Porifera, are multicellular organisms that have bodies full of pores and channels which allow water to move through them. Sponges are classified on the basis of different types of spicules which are made up of calcium carbonate. Demospongia where the spicules are made up of siliceous spicules or spongin fibres or both, Hexactinellida where the spicules are made up of silica.
Euplectella, also known as Venus basket flower or glass sponge, is a hexactinellid sponge. These consist of siliceous fibres and it builds its skeleton from silica. These sponges show bioluminescence to attract plankton and sponges are growing in the form of a cornucopia. It consists of a house of two small shrimps (male and female) inside its glass skeleton. When young shrimp are small they enter into sponge and then they become big to get out. And then they spend their rest of life trapped in a glass house. The relationship between the sponge and the shrimp is symbiotic in nature.

The correct option is B- Euplectella.

Note: Euplectella is a genus of glass sponge. When the shrimp procreate, the offspring are small enough to leave the sponge to find a new flower basket. This deep sea love story is the most romantic example of “till death do us apart” in the animal kingdom.