Science Quiz For 5th Standred

Explanation
The correct answer is 21%. In the air, approximately 21% of the total volume is composed of oxygen. This level of oxygen is crucial for the survival of many living organisms, including humans. Oxygen is necessary for respiration, allowing cells to produce energy. The majority of the remaining air is made up of nitrogen, with trace amounts of other gases such as carbon dioxide and argon.

Explanation
A doctor's syringe makes use of air pressure to create suction and push fluids in and out of the syringe. When the plunger is pulled back, it creates a vacuum inside the syringe, causing the fluid to be drawn into the syringe. When the plunger is pushed, it increases the pressure inside the syringe, forcing the fluid out. Air pressure plays a crucial role in the functioning of a doctor's syringe by facilitating the movement of fluids.

Explanation
The correct answer is "the blanket of layer surrounding our earth." This answer accurately describes the atmosphere as a layer of gases that surrounds the Earth, acting like a protective blanket. It helps regulate temperature, protects against harmful radiation, and plays a crucial role in supporting life on our planet.

Explanation
The brain is often referred to as the "human computer" because it is responsible for processing and storing vast amounts of information, just like a computer. It controls all bodily functions, including thinking, memory, emotions, and movement. The brain contains billions of neurons that communicate with each other through electrical and chemical signals, allowing us to perceive the world, make decisions, and carry out complex tasks. Its intricate network of connections and ability to process information make it the most important organ in the body, earning it the nickname "human computer."

Explanation
The skeleton provides support to our body by serving as a framework that holds our body upright. It also protects our internal organs and provides attachment points for muscles, allowing for movement and mobility. Without the skeleton, our body would not have the necessary structure and stability to function properly.