The order of flow of oxygen within the human body may be described simply. Oxygen first is inhaled through the nasal cavity and then passes through the trachea, through the bronchi and into the lungs. In the lungs, the oxygen is passed into the blood stream through the alveoli and then is carried to the heart. The heart pumps this oxygenated blood throughout the body, primarily to organs and muscle cells, where it is consumed in respiration and is converted to carbon dioxide and excreted.
Answer:
Artifical Selection OR Cross Pollination
Explanation:
If white roses and red roses are cross-bred by scientists, it would be artifical selection. If they were crossed in nature, it is called crossed pollination.
Heat from the Sun causes water to evaporate from the surface of lakes and oceans. This turns the liquid water into water vapor in the atmosphere. Plants, too, help water get into the atmosphere through a process called transpiration!
Earth's crust is made of rock, and rock is made of natural substances called minerals. There are three main types of rock: sedimentary, igneous, and metamorphic rock. Each type is produced in different ways. The oldest rocks on Earth were formed about 3.8 billion years ago.
An element's atomic number is the amount of protons (positively charge subatomic particle found in the atoms nucleus) present in one atom of that element.
