NDA (II) 2021 General Ability Test · Question 133 of 149

Correct — A, Four. Cattle, buffalo, goat and sheep are ruminants, and a ruminant's stomach has four chambers — the rumen, reticulum, omasum and abomasum. The first three chambers store and ferment the coarse plant food with the help of microbes, and the abomasum is the 'true' stomach that digests with acid and enzymes as ours does. So the total number of chambers is four.

• (b)Two — Two chambers do not match ruminant anatomy; the ruminant stomach is famously four-chambered.
• (c)One — A single-chambered (simple) stomach is what non-ruminants like humans, dogs and pigs have — not cattle, buffalo, goat and sheep.
• (d)Three — Three is a common trap, but the ruminant stomach has four chambers, not three — the fourth is the abomasum, the true digestive stomach.

Ruminants are cud-chewing herbivores whose stomach is divided into four compartments: rumen, reticulum, omasum and abomasum. Because grass and leaves are hard to digest, food is first fermented by micro-organisms in the rumen, brought back up as cud and chewed again, then passed through the reticulum and omasum before the abomasum digests it. This lets them extract nutrients from fibrous plant matter, and the gut microbes even supply some vitamins.

The clue is the list of animals — all are ruminants (cud-chewers). Ruminant means a four-chambered stomach. Non-ruminant mammals such as humans have a single-chambered stomach, which is the tempting 'one', while 'three' is the near-miss.

• Cattle, buffalo, goat and sheep are ruminants (cud-chewing herbivores).
• Their stomach has four chambers: rumen, reticulum, omasum and abomasum.
• The rumen ferments coarse plant food with microbes; the abomasum is the 'true' stomach.
• Ruminants regurgitate and re-chew partially digested food (cud) to break down cellulose.

• Picking 'three' — the ruminant stomach has four chambers, not three.
• Assuming all mammals have a single stomach like humans; ruminants are the exception.

Asked as the number of stomach chambers in named ruminants — recall the four-chambered ruminant stomach.

No directly related past PYQ was found.

• practice — not a real PYQ

  The largest chamber of a ruminant's stomach, where microbial fermentation of grass occurs, is the

  • (a)Abomasum
  • (b)Rumen
  • (c)Omasum
  • (d)Reticulum

  Answer(b) Rumen — the large fermentation chamber.

• practice — not a real PYQ

  Which one of the following animals has a single-chambered (simple) stomach?

  • (a)Cow
  • (b)Goat
  • (c)Horse
  • (d)Sheep

  Answer(c) Horse — it is a non-ruminant herbivore with a simple stomach.