Barack Obama received the Nobel Peace Prize in 2009, so 2009 is the correct year.

Passed in March 1949, setting Islamic principles for Pakistan’s constitution, per historical records.

Duplicate of Q15. Nanocomposites protect against environmental factors (Journal of Food Engineering).

Duplicate of Q2. Microphones convert sound to electrical audio signals (audio engineering sources).

The Paris Agreement (2015) targets limiting global warming to below 2°C, unlike Kyoto (1997) or Copenhagen (2009), per UN climate records.

Nanocomposites enhance packaging barriers against moisture, heat, and other environmental factors (including flood and fire damage), per food technology research (e.g., Journal of Food Engineering).

Machine learning is a subset of AI, focusing on data-driven algorithms, distinct from hardware engineering or cyber forensics, per AI texts (e.g., “Artificial Intelligence: A Modern Approach”).

A microphone converts mechanical sound waves into an electrical audio signal, as confirmed by audio engineering references (e.g., “Fundamentals of Audio Engineering”).

A step-up transformer increases voltage by having more turns in the secondary coil than the primary, as per transformer principles in standard physics texts (e.g., Halliday & Resnick).

In 2006, Dick Cheney was the incumbent Vice President of the United States, serving under President George W. Bush [1, p13]. Cheney held the office from January 20, 2001, to January 20, 2009. The provided PDF's answer key incorrectly marks (d) and its explanation is not relevant to the 2006 timeframe [1, p13].