Meaning: 'Perceived' means to become aware of something through the senses, particularly sight, indicating how the observer sees the color red in the rainbow.

Wrong options:

• received: Received implies obtaining something, which does not fit the context of visual observation.
• promote: Promote means to support or encourage, which is unrelated to the act of seeing or observing colors in a rainbow.
• patient: Patient refers to someone who is receiving medical care or the quality of being able to accept delays, which does not relate to the observation of colors.

Correct answer: actually

Explanation: The word 'actually' serves as an adverb that emphasizes the truth of the statement, indicating that a rainbow can indeed be a complete circle, which is a factual assertion in this context.

Meaning: 'Actually' means in fact or really, used to confirm the reality of the situation regarding the visibility of a rainbow from an airplane.

Wrong options:

• rarely: Rarely suggests infrequency, which contradicts the assertion that a rainbow can be a complete circle.
• hardly: Hardly implies something is almost not true, which does not fit the context of confirming the existence of a complete circle.
• normally: Normally indicates what is usual or expected, which does not emphasize the factual nature of the statement as effectively as 'actually'.

Correct answer: collection

Explanation: The word 'collection' fits grammatically as a noun that refers to a group of items, in this case, droplets. It contextually aligns with the idea of multiple droplets working together to create the phenomenon of a rainbow.

Meaning: 'Collection' means a group of items gathered together, referring to the droplets in the atmosphere that contribute to the formation of a rainbow.

Wrong options:

• selection: Selection implies a choice made from a group, which does not accurately describe the droplets as they are not chosen but rather exist in a group.
• implication: Implication refers to a suggestion or consequence, which does not fit the context of describing a physical group of droplets.
• mutation: Mutation refers to a change or alteration, which is unrelated to the concept of droplets forming a rainbow.

Correct answer: deviation

Explanation: The word 'deviation' fits grammatically as a noun that describes a departure from a standard or expected path. It contextually relates to the angles at which light is refracted by the droplets to create a rainbow.

Meaning: 'Deviation' means a departure from an established course or norm, in this case, the angles of light relative to its original path.

Wrong options:

• concentration: Concentration refers to the amount of something in a given space, which does not relate to the angles of light in this context.
• elevation: Elevation refers to height above a reference point, which does not apply to the angles of light in the formation of a rainbow.
• alignment: Alignment refers to arrangement in a straight line or correct relative positions, which does not accurately describe the angles involved in light dispersion.

Correct answer: dispersing

Explanation: The word 'dispersing' fits grammatically as a present participle that describes the action of the droplets. It contextually aligns with the process of light being spread out as it interacts with each droplet in the arc.

Meaning: 'Dispersing' means spreading out or scattering, referring to how light is distributed by the droplets in the rainbow.

Wrong options:

• omitting: Omitting means leaving something out, which contradicts the action of light being reflected and seen in the rainbow.
• orbiting: Orbiting refers to moving around a central point, which does not accurately describe the action of light in this context.
• area: Area refers to a measure of space, which does not fit the action of how light interacts with the droplets.