Chapter 23, Problem 4A

Summary Introduction

Introduction :

The sporophytic and gametophytic stages are the two stages of fern life cycle. The sporophyte plants are diploid while the gametophyte plants are haploid. This phenomenon of life cycle is considered as alternation of generations. In the very first stage, the spores are formed and germinate to grow into small heart-shaped plant that are the gametophytes. Both the egg and sperm cells are formed in the gametophyte and fertilized it, ones the fertilization over the adult fern will start growing. In the second stage of life cycle the fertilized gametophytes look like a mossy growth this will developed to young fronds rising out of the moss.

Answer to Problem 4A

Correct answer :

The correct answer is option (B).

Explanation of Solution

Explanation/justification for the correct answer :

Option (B) The picture represented in B is of fern pothallus. It is the gametophyte stage of fern life cycle. This will develop and germinate to spore. So, the correct answer is option (B).

Explanation for incorrect answer :

Option (A) The picture represented in A is of developed fern. This consist of sori underside of the leaves where reproductive spores has been stored.So, this is an incorrect option.

Option (C) The picture represented in C is of young gametophyte. The spore released from sporangium form a small heart shaped plant.So, this is an incorrect answer.

Option (D) The picture represented in D is of sporangium that release spores for the germination process and develop into a gametophyte.So, this is an incorrect answer.