Chapter 26, Problem 5STP

Summary Introduction

Introduction :

The flateworms are belongs to the branch acodomate of the evolutionary tree and of phylum Platyhelminthes. They have bilateral body symmetry; the bilateral body has the ability to evolve different organs. The flatworms are parasitic in nature they found inside the body of different animal. They feed on dead organisms with the help of pharynx that is a long tube-like extension found in mouth. They do not have respiratory and circulatory organs as their body is so flat and thin that they possess the respiration process through diffusion. The reproduction processes in flatworm are both sexual and asexual as they are hermaphrodites they produce both sperm and eggs. The sperm help the egg to fertilized inside or release the zygote in the water. In the asexual reproduction they regenerate.

Answer to Problem 5STP

Correct answer :

The correct answer is option (D) regeneration.

Explanation of Solution

Explanation/justification for the correct answer :

Option (D) regeneration. The flatworms during asexual reproduction undergo regeneration. They have the ability to regenerate any damage part of the body. If their head is cut horizontally they will grow a new head. So, the correct answer is option (D).

Explanation for incorrect answer :

Option (A) budding. Budding is an asexual process in which the organism will form a new progeny from a part of its parent body. Such reproduction is followed by unicellular organisms. So, this is an incorrect option.

Option (B) fertilization. Fertilization is a sexual reproduction process in which the sperm of male species help to fertilize the egg of female species to form zygote. So, this is an incorrect answer.

Option (C) parthenogenesis. Parthenogenesis is a reproduction process in which the egg of the organism undergoes embryo formation without getting fertilized. Organism such as bees, scorpion, nematodes, etc., are parthenogens. So, this is an incorrect answer.