Step 1: Analyze Assertion (A)
The statement is correct. Biology has seen rapid advances in the last three decades due to biotechnology, genomics, and molecular techniques.
Step 2: Analyze Reason (R)
While the invention of microscopes and the study of sexual reproduction contributed historically, they were not the primary reason for recent rapid progress. Thus, this reason is outdated and incorrect for this context.
Step 3: Examine the explanation relationship
Since (R) is false, it cannot explain (A).