Chapter 21, Problem 23A

Summary Introduction

Introduction :

The spore-producing process in the life cycle of a plant is called sporophyte. There are 2 reproductive stages in plants: sexual and asexual. The alternation of generation secretes these two phases into the sporophyte and gametophyte via the cycle of meiosis and fertilization. Sporophyte is the phase when plants produce diploid (2n) spores which develop into gametophytes in turn to spores.

Answer to Problem 23A

Correct answer :

The correct answer is option (D)

Explanation of Solution

Explanation/justification for the correct answer :

Option (D) The picture indicates the bird’s nest ferns and it consist of sori. It is a cluster of sporangia that is found on the undersides of the frond. The fern in the picture does not show strobilus. So, the correct answer is option (D).

Explanation for incorrect answer :

Option (A) The picture indicates the horsetail structure. It produces strobili at the tip of the reproductive stems. During favorable condition, this horsetail spores form gametophytes. So, this is an incorrect option.

Option (B) The picture indicates the club moss. It consists of strobilus which means a compact cluster of spore bearing structure. So, this is an incorrect answer.

Option (C) The picture indicates the Lycopodium or wolf’s claw. It shows strobilus structure in the tip that consists of a cluster of spore. So, this is an incorrect answer.