Chapter 21, Problem 21A

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 21A

Correct answer :

The correct answer is option (A) sorus.

Explanation of Solution

Explanation/justification for the correct answer :

Option (A) sorus. In seedless vascular plants the fern forms spores inside a structure that is considered as sporangium and cluster of sporangia to form a sorus. They are found on the underside of the fronds. It shows the horsetail structure. So, the correct answer is option (A).

Explanation for incorrect answer :

Option (B) frond. Fronds is a photosynthetic leafy structure of fern. It is a part of sporophytic generation. It has branched vascular tissue of different size. So, this is an incorrect option.

Option (C) stem. Stem is a part of plants that involve in the transportation and absorption of nutrients. So, this is an incorrect answer.

Option (D) blade. Blade is a part of leaf that give the shape to the leaf. It is not spore bearing. So, this is an incorrect answer.