Answer : The product in the given balanced reaction is, sulfur dioxide
.
Explanation :
The balanced chemical reaction will be,

This reaction occurs when sulfur react with oxygen gas to give sulfur dioxide gas as a product.
In the given balanced chemical reaction, sulfur (S) and oxygen gas
are the reactants and sulfur dioxide
is the product.
Hence, the product in the given balanced reaction is, sulfur dioxide
.
Biochemical- apart of the second defense system
Answer:
Increase in transcription
Explanation:
Transcription is the process of forming RNA from DNA. It can be controlled by many factors like a repressor. Repressor can bind to the operator region of the promoter and hinder the movement of RNA Polymerase enzyme, halting the process.
Here, it is given that the repressor needs to first bind to an effector molecule X. Once it binds to X, it is activated and then it can bind to operator of gene A to inhibit its transcription. If the X binding domain on repressor is mutated it wont be able to bind to X. Thus it wont get activated and wont be able to attach to operator region to inhibit transcription. Hence, transcription process will keep going on uncontrolled.
B. The levels of classification increased. Previously there were only 2 domains of life, Bacteria and Eukarya, but an additional domain and Kingdom were added when the distinction of Archaea was observed.