Question

This is a figure of a typical annelid, earthworm. Identify and label the parts from A to H

• A. A- Mouth, B- nerve cord, C- nerve ring brain, D- pharynx, E- heart, F- blood vessels, G- gizzard, H- crop
• B. A- Mouth, B- nerve ring brain, C- nerve cord, D- pharynx, E- heart, F- blood vessels, G- crop, H- gizzard
  
• C. A- Mouth, B- nerve cord, C- nerve ring brain, D- heart, E- pharynx, F- blood vessels, G- crop, H- gizzard
  
• D. A- Mouth, B- nerve cord, C- nerve ring brain, D- pharynx, E- heart, F- blood vessels, G- crop, H- gizzard
  

Answer 1

The correct option is D A- Mouth, B- nerve cord, C- nerve ring brain, D- pharynx, E- heart, F- blood vessels, G- crop, H- gizzard

Food enters into the mouth (A) where it is swallowed by pharynx (D). After that, food passes through the oesophagus, the food moves into the crop (G) where it is stored and then eventually moves into the gizzard (H). The gizzard uses stones that the earthworm eats to grind the food completely. The earthworm has a closed circulatory system. An earthworm circulates blood exclusively through vessels (F). There are three main vessels that supply the blood to organs within the earthworm. These vessels are the aortic arches, dorsal blood vessels, and ventral blood vessels. The aortic arches function like a human heart (E). Central nervous system of earthworm consists of two parts nerve cord (B) and nerve ring brain (C). Nerve ring is a ring like spherical structure which lies around the pharynx in 3rd and 4th segment. Ventral nerve cord is a long thread like double layered structure, which arises from the posterior part of sub-pharyngeal ganglia and runs the posteriorly up to the last segment of the body.

Therefore, the correct answer is option D.