Organism that bore into or grow inside a substrate:

Correct option is D

Correct Answer: (d) Endobenthos
Explanation:
→ Endobenthos are organisms that live within the sediment matrix (burrowers, borers) — e.g., infaunal polychaetes, some bivalves.
→ They influence sediment structure, aeration and nutrient recycling.
Information Booster:
→ Endobenthic activity (bioturbation) enhances oxygen penetration and nutrient fluxes to the water column.
Additional Information (Other Options):
(a) Rhizobenthos: root-associated.
(b) Haptobenthos: surface-attached.
(c) Herpobenthos: surface-crawling.