The importance of water to human beings

Water is very important to us. It is indispensable for humans, animals, plants, etc. We humans cannot survive without water. It is said that people can go without food for a week as long as they stay hydrated every day. We need a lot of water every day. For example, taking a bath, washing clothes, and other activities cannot be done without water. Some plants need water to grow, and animals also need water resources.

Question 1

1. Water plays an important role in our lives. It is the source of life and one of the most important and indispensable material resources for human survival and development. Human life cannot be separated from water for a moment. Water is the most important substance required for human life. The human body has many aspects of physiological functions, and all chemical reactions in the body take place in the medium of water. Without water, nutrients cannot be absorbed, oxygen cannot be transported to the required parts, nutrients and hormones cannot reach their sites of action, waste cannot be eliminated, metabolism will stop, and people will die. Therefore, water is the most important substance for human life. On Earth, wherever there is water, there is life. All life activities originate from water. Water in the human body accounts for about 65% of body weight. Among them, the brain contains 75% water, the blood contains 83% water, the muscles contain 76% water, and even the hard bones contain 22% water! Without water, nutrients in food cannot be absorbed, waste cannot be excreted from the body, and drugs cannot reach the site where they work. Once the human body lacks water, the consequences will be very serious. A 1%-2% water shortage will cause thirst; a 5% water shortage will cause dry mouth, wrinkled skin, confusion, and even hallucinations; a 15% water shortage is often worse than hunger. Without food, people can survive for a long time (some estimate it to be two months), but without even water, they can only survive for about a week at most.

2. In modern industry, there is no industrial sector that does not use water. There is no industry that does not have direct or indirect contact with water. More industries use water to cool equipment or products, such as steel mills. Water is also often used as a detergent, such as rinsing raw materials or products, cleaning equipment or floors. Every factory uses water in various ways to maintain normal production, and water is involved in almost every production link.

Therefore, water, as a precious treasure bestowed by nature on mankind, has long been the focus of people's attention. However, people have only begun to use the term "water resources" frequently in the last ten or twenty years. There are dozens of definitions of water resources. The more common one refers to "the amount of water that is available for regular use by people and can be restored year by year." This is what is usually referred to as freshwater resources. In this way, the bitter and salty sea water is not included, and even the glaciers that have been difficult to melt for thousands of years and some groundwater that is difficult to access are also excluded. The clear resources are the ones that humans have investigated and understood most clearly. Their quantity structure and distribution will never change due to new major discoveries like coal, iron, oil and other resources. The value of water resources lies in the fact that they meet the needs of life on Earth and serve humanity, including their ability to generate electricity, shipping, aquaculture, and the environment. We all know that water is an extremely important and active factor in both the natural and social environments. Beautiful mountains and clear waters, singing birds and blooming flowers, good weather and abundant harvests are the beautiful scenery that mankind pursues and yearns for, and are also the fruits of human labor and careful care. Water is constantly moving, in the human body, in farmlands, and in factories, making the world full of life and vitality. Pollution is carried away, diluted, dissolved, and purified by the water flow. When we wander in the embrace of nature, in fact, all we face is the power given to us by water. In our life of mountains, trees, crops and water, water gives us a large proportion. The earth is known as the "water ball". The saying "three mountains, seven rivers and one piece of farmland" vividly summarizes the situation on the earth's surface. According to authoritative estimates, the earth's water storage capacity is 385 million cubic kilometers. If these volumes were spread out on the surface of the earth, the earth would become a "water ball" with an average water depth of more than 2,700 meters. When sailing in the sea, although the waves lift you up and the waves play with you, you dare not drink a drop of sea water, even if you are so thirsty that your throat is smoking and your lips are cracked. 97% of the water on Earth is seawater, which currently cannot be drunk directly by humans.