Vitamin D plays a crucial role in calcium absorption in the gut and maintaining adequate serum calcium and phosphate levels.

Vitamin A is essential for the formation of rhodopsin, a pigment in the retina that is crucial for vision.

Vitamin C is abundant in citrus fruits like oranges, lemons, and grapefruits.

Vitamin D is synthesized in the skin upon exposure to sunlight.

Vitamin A is essential for vision, particularly in low-light conditions.

Vitamin D is produced in the skin when it is exposed to sunlight.

Vitamin D is synthesized in the skin when it is exposed to ultraviolet (UV) rays from sunlight.

The passage characterizes digital sum as innovative, highlighting its modern applications.

Green light is least effective for photosynthesis because it is mostly reflected by chlorophyll.

Blue light is most effective for photosynthesis as it is absorbed strongly by chlorophyll.

The Pradhan Mantri Awas Yojana, launched in 2015, aims to provide affordable housing to the urban poor.

The Skill India Mission, launched in 2015, aims to provide skill training to the youth to enhance their employability.

The author expresses an urgent sentiment towards environmental conservation, stressing its importance.

The author expresses a hopeful sentiment towards conservation efforts, suggesting optimism for the future.

The author expresses indignation towards the growing economic inequality in society.

The author adopts an urgent tone, emphasizing the immediate need for environmental conservation efforts.

The author expresses frustration with current environmental policies, indicating a critical tone.

'Therefore' indicates a cause-and-effect relationship.

'Therefore' indicates that his preparation was a result of his studying.

The author shows an understanding attitude, recognizing the concerns of skeptics while advocating for action.

The author views education as critical for raising awareness and fostering informed action on climate change.

The findings are described as groundbreaking, indicating their significant impact on the field.

The context suggests a positive reaction, making 'enthusiasm' the most fitting choice.

In the context of the passage, 'ameliorate' means to improve, making option B the correct replacement.

'Improve' is the best replacement for 'ameliorate', as both words convey the idea of making conditions better.

In the context of the passage, 'mitigate' means to reduce the severity of an issue, making 'reduce' the best replacement.

'Ubiquitous' means present everywhere or widespread, so 'common' is the best replacement in this context.

'Common' is the best replacement for 'ubiquitous', as it conveys the idea of smartphones being widely present in society.

Carrot is a vegetable, while the others are fruits.

Timid is an antonym of the other three words.