Description of veterinary medical equipment model design

The atmosphere is also called the atmosphere, and the earth is surrounded by this thick atmosphere. The main component of the atmosphere is nitrogen, accounting for 78.1%; Oxygen accounts for 20.9%; Hydrogen accounts for 0.93%; There are also a small amount of carbon dioxide, rare gases (helium, neon, argon, krypton, xenon, radon) and water vapor. The air density of the atmosphere decreases with the increase of altitude. The higher the air, the thinner the air. The thickness of the atmosphere is about 1000 km, but there is no obvious boundary. The whole atmosphere shows different characteristics with different heights, which is divided into troposphere, stratosphere, mesosphere, warm layer and escape layer, and then interstellar space.

The hydrosphere is the most active layer in the outer circle of the earth. Its interaction with the atmosphere, biosphere and the inner circle of the earth is directly related to the evolution of the surface system that affects human activities. The hydrosphere is also the main medium of external dynamic geological processes and the most important role in shaping the earth's surface.

Biosphere is an area where the influence of life activities on the earth occurs and is felt. It is the general name of surface organisms including microorganisms and their bottom-up environment, and it is a unique circle of planet earth. It is also the space where human beings are born and live.

Lithosphere (lithosphere)

The outermost layer of the earth is elastic hard rock with an average thickness of about 100 km. It consists of the crust and the top of the upper mantle. Below the lithosphere is the asthenosphere. The lithosphere can be divided into six plates: Eurasia plate, Pacific plate, America plate, Africa plate, Indo-Oceania plate and Antarctica plate. There are also some smaller plates embedded in it. There are four types of plate boundaries: ridge plate expansion zone, island-gully plate subduction zone, transformation fault zone and continental collision zone. (See the internal structure of the earth).