“Biorock technology” is talked about in which one of the following situations?

Answer: (a) Restoration of damaged coral reefs

Biorock (mineral accretion): a low-voltage current through a steel frame on the seabed makes calcium carbonate and other minerals deposit on it. Coral fragments tied to it grow fast and cope better with heat stress.

The idea

A coral builds its skeleton from calcium carbonate taken from sea water, which costs it energy. Biorock gives the coral a ready-made limestone base and makes the water around it favourable for building, so the coral can spend its energy on growth.

Steel frame on the seabed → Low-voltage current (safe for divers) → Limestone coats the frame → Coral fragments grow on it

Why the others are wrong

(b) Building materials from plant residue have nothing to do with biorock.

(c) Shale-gas exploration uses seismic surveys, not biorock.

(d) Salt licks are natural or artificial mineral licks for animals.

The trap

“Rock” pulls you towards building materials or shale (b, c). The “bio” is the clue: a living reef.

Also know

In India, the Zoological Survey of India has tried biorock to restore corals in the Gulf of Kachchh (Gujarat).