The decomposition rate is slower if detritus is rich in-

The correct answer is Option (4) → Chitin

Decomposition is the breakdown of detritus, the dead remains of plants and animals, by decomposers. How fast it goes depends on the chemical make-up of the detritus and on the climate: warm, moist conditions speed it up, while cold and lack of oxygen slow it down.

Option (1) Nitrogen — Incorrect. Detritus rich in nitrogen decomposes faster, because decomposers need nitrogen to grow.

Option (2) Sugars — Incorrect. Sugars are water-soluble and easy to use, so they make decomposition quicker.

Option (3) Cellulose — Incorrect. Cellulose is the carbohydrate of plant cell walls. Microbes break it down more slowly than sugars, but the book names lignin and chitin as the materials that slow decomposition.

Option (4) Chitin — Correct. Chitin is the tough material of insect exoskeletons and fungal cell walls. Few decomposers can break it down, so detritus rich in chitin decays slowly.

NCERT Extract:
Decomposition – …