Fruits stored in a cold chamber exhibit longer storage life, because

1. A

   Exposure to sunlight is prevented

   Option (a) claims that fruits stored in cold chambers last longer because exposure to sunlight is prevented. Sunlight is already typically excluded in standard indoor storage, making this an insufficient explanation for the extended shelf life.

2. B

   Concentration of CO in environment is 2 increased

   Option (b) claims that the concentration of CO2 is increased in the environment. While controlled atmosphere storage does manipulate gases, the primary universal mechanism of cold storage is temperature reduction, not CO2 accumulation alone.

3. C

   Rate of respiration is decreased

   Option (c) claims that the rate of respiration is decreased, which is the core physiological reason for extended storage life. Low temperatures in cold chambers slow down enzymatic activity and metabolic processes, significantly reducing the respiration rate of fruits and delaying ripening and decay, thus making this the correct key.

4. D

   There is an increase in humidity

   Option (d) claims that there is an increase in humidity. Although humidity management prevents moisture loss and shriveling, it is not the primary metabolic reason for the overall extension of storage life compared to respiration control.

Summary. Official key is (c) Rate of respiration is decreased. Fruits continue to respire after harvest, consuming oxygen and sugars while releasing heat, water, and ethylene gas. Lowering the ambient temperature inside a cold chamber drastically slows down this metabolic respiration rate. Consequently, the ripening process is delayed, tissue breakdown is minimized, and the storage life of the fruits is significantly prolonged. This direct physiological impact of temperature on respiration rate is the definitive scientific principle behind cold storage efficacy.