Introduction:
In space, several elements that are commonly found on Earth are not present. These elements include gravity, water, and food. The correct answer to the question is option 'D,' which states that all of these elements are not present in space.

Gravity:
Gravity is the force that attracts objects towards each other. It is what keeps us grounded on Earth and gives weight to objects. However, in space, the gravitational force is significantly weaker or absent altogether. This absence of gravity allows astronauts to experience weightlessness and enables them to float freely inside spacecraft.

Water:
Water is a vital element for life on Earth. It is essential for hydration, as well as for various bodily functions. However, in space, water is not naturally present in its liquid form. Instead, it exists in the form of ice or vapor. Astronauts must carry their own supply of water or rely on water-reclamation systems to recycle and purify their water.

Food:
Food is another element that is not naturally present in space. Astronauts require specially packaged and preserved food for their missions. These food items undergo extensive processing to ensure they are safe and suitable for consumption in space. They are typically dehydrated, freeze-dried, or packaged in airtight containers to prolong their shelf life.

All of these:
The correct answer to the question is option 'D' because all of these elements - gravity, water, and food - are not present in space. The absence of gravity leads to a weightless environment, while the lack of water and food requires astronauts to bring their own supplies or rely on advanced systems to sustain themselves during space missions.

Conclusion:
Space is a unique environment that lacks several elements commonly found on Earth. The absence of gravity, water, and food presents challenges for astronauts, requiring them to adapt and bring their own supplies to sustain themselves during space missions. Option 'D' correctly identifies that all of these elements are not present in space.