Golden Rice, a genetically modified variety of rice, is pale yellow in color primarily because it is especially rich in which pigment or nutrient?

Introduction / Context:
Golden Rice is a well known example of genetically modified food developed to address vitamin A deficiency in many parts of the world. Its distinctive pale yellow color is a visual clue to its nutritional enhancement. Understanding why this color appears connects genetics, plant biochemistry, and public health, making it a popular topic in biology and general science exams.

Given Data / Assumptions:
The question asks why Golden Rice is pale yellow.
Options mention beta carotene, phycobilins, chlorophyll, and an option that none is correct.
We assume the student knows that Golden Rice is engineered to produce a specific nutrient in the rice endosperm.
The focus is on identifying the pigment responsible for the golden color.

Concept / Approach:
Golden Rice has been genetically engineered to produce beta carotene in the rice endosperm, which normally does not synthesize this compound. Beta carotene is an orange to yellow pigment that acts as a precursor of vitamin A in the human body. When people eat Golden Rice, their bodies can convert beta carotene into vitamin A, helping reduce deficiency. Phycobilins are pigments found mainly in certain algae and cyanobacteria. Chlorophyll is the green pigment involved in photosynthesis, and although rice plants contain chlorophyll in their leaves, the grains of Golden Rice look yellow mainly because of beta carotene in the endosperm. Therefore, beta carotene is the correct answer.

Step-by-Step Solution:
Step 1: Recall that Golden Rice is designed to help combat vitamin A deficiency. Step 2: Remember that beta carotene is a precursor of vitamin A and has a yellow to orange color. Step 3: Note that Golden Rice grains appear pale yellow due to the accumulation of beta carotene in the endosperm. Step 4: Compare this knowledge with the options and choose beta carotene.

Verification / Alternative check:
Reports and textbook descriptions of Golden Rice consistently mention that it has been engineered to produce beta carotene. They also show images of rice grains with a golden or yellowish tint. Chlorophyll, which is green, is present mainly in leaves and not responsible for the color of the grain. Phycobilins are specialized pigments in algae and are not typically linked with rice grains. This confirms that beta carotene is the correct pigment responsible for the pale yellow color.

Why Other Options Are Wrong:
Phycobilins are accessory pigments in certain algae and cyanobacteria and are not used to color or fortify rice.
Chlorophyll gives a green color to leaves and other photosynthetic tissues, not a pale yellow color to rice grains.
The option none of these is incorrect because beta carotene clearly explains both the color and the nutritional goal of Golden Rice.

Common Pitfalls:
Some students might wrongly associate any plant pigment with chlorophyll, forgetting that it is specifically green. Others may not recall the name beta carotene and may be tempted by none of these even when they faintly recognize the connection to vitamin A. Remembering that carotene rich foods such as carrots are orange and that Golden Rice uses the same principle helps fix this answer in memory.

Final Answer:
Golden Rice is pale yellow because it is rich in Beta carotene.