Question

One very special feature of the earthworm Pheretima is that?

• A. Fertilisation of eggs occurs inside the body
• B. The S-shaped setae embedded in the integument are the defensive weapons used against the enemies
• C. The typhlosole greatly increases the effective absorption area of the digested food in the intestine
• D. It has a long dorsal tubular heart

Answer 1

The correct option is C

The typhlosole greatly increases the effective absorption area of the digested food in the intestine

The correct option is C

Explanation for correct option:

1. It's a dorsal flap of the intestine in earthworms that spans the length of the tube, thereby constructing a tube within a tube and boosting the absorption area by the inner surface.
2. Its goal is to expand the intestine's surface area in order to optimize nutrient absorption.

Explanation for Incorrect option:

Option A:

1. Almost all flatworm species are hermaphroditic, which means they reproduce sexually.
2. Self-fertilization is conceivable in several species, even though gamete exchange is the most common method.
3. It has the ability to make eggs and fertilize them with sperm produced in its own body.

Option B:

1. Except for the first, last, and clitellar segments, the entire body of an earthworm is covered in stiff ‘S-shaped’ bristles.
2. These setae serve a crucial role in the movement.

Option D:

1. The blood vessels in Pheretima are of the close kind. It includes blood vessels and the heart.
2. There are four sets of tubular hearts in earthworms.
3. These hearts have thick walls, are pulsatile, and have valves.

Final answer: One very special feature of the earthworm Pheretima is that typhlosole greatly increases the effective absorption area of the digested food in the intestine.