Answer:

B. oxygen

Explanation:

• Fruit turns brown when exposed to air because a reaction is happening when a cut piece of fruit is exposed to oxygen. ... The chemical reaction can be simplified to: Polyphenol Oxidase + O2 → Melanin (Brown Color) Oxygen activates the compound polyphenol oxidase in the fruit to turn the fruit brown.

Answer:

B. OXYGEN

Why do apples turn brown?

Apples turn brown because of enzymatic browning. This process requires three things:

1.Oxygen.

2.A special enzyme called polyphenol oxidase (PPO).

3. Polyphenols, which are also called phenolic compounds. These are complex organic molecules which contain at least one hydroxyl group (-OH) bonded to a hydrocarbon ring (C6H5).

Explanation:

When an apple is cut (or bruised), oxygen is introduced into the injured plant tissue. When oxygen is present in cells, polyphenol oxidase (PPO) enzymes in the chloroplasts rapidly oxidize phenolic compounds naturally present in the apple tissues to o-quinones, colorless precursors to brown-colored secondary products.

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