Yellowing is a chemical sign of deterioration, not a physical one.

Exposure to light is the primary cause of fading in photographs, as it breaks down the silver halide crystals that form the image.

Brittle film base, silver mirroring, and fungal growth are all chemical signs of deterioration in photographs.

Cracking in photographs can be caused by improper handling, high humidity, exposure to heat, or a combination of these factors.

Low humidity is not a common environmental factor that contributes to the deterioration of photographs.

The recommended temperature range for storing photographs to minimize deterioration is 40-50°F.

Storing photographs in a plastic sleeve is not a recommended storage method, as it can trap moisture and accelerate deterioration.

High humidity is the primary cause of fungal growth on photographs.

All of the options listed are recommended methods for preventing fungal growth on photographs.

Improper storage, such as storing photographs in a humid or acidic environment, is the primary cause of silver mirroring.

All of the options listed are recommended methods for preventing silver mirroring in photographs.

Warping in photographs can be caused by exposure to heat, high humidity, improper storage, or a combination of these factors.

All of the options listed are recommended methods for preventing warping in photographs.

Improper storage, such as storing photographs in a hot or humid environment, is the primary cause of brittle film base.

All of the options listed are recommended methods for preventing brittle film base in photographs.