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Biology Question 101 – NEET-UG 2023

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Given below are two statements : One is labelled as Assertion A and the other is labelled as Reason R : Assertion A : The first stage of gametophyte in the life cycle of moss is protonema stage. Reason R : Protonema develops directly from spores produced in capsule. In the light of the above statements, choose the most appropriate answer from the options given below :

Recall the life cycle of mosses, specifically the stages of the gametophyte.

Step 1: Analyze Assertion A✦ Active

Assertion A states that the first stage of the gametophyte in the life cycle of moss is the protonema stage. This statement is biologically correct. In mosses (Bryophytes), the haploid spores germinate to form a filamentous, branched, green structure called the protonema, which represents the juvenile gametophyte.

Step 2: Analyze Reason R○ Expand

Reason R states that the protonema develops directly from spores produced in the capsule. This statement is also biologically correct. The sporophyte of mosses produces spores within its capsule, and these spores are dispersed and germinate to form the protonema.

Step 3: Evaluate Relationship between A and R○ Expand

The protonema is considered the first stage of the gametophyte (Assertion A) precisely because it develops directly from the germination of spores (Reason R), which are the propagules that initiate the gametophytic generation. Therefore, Reason R provides a correct explanation for Assertion A.

💡 Teacher's Secret Hint

For assertion-reason questions, first check if both statements are individually correct, then determine if the reason logically explains the assertion.

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