The Sun is the main cause for our weather, and different season (in different areas where you live it depends on how hot or cold it is also caused by the sun)
Most seasons, like in summer it's hot Also caused by the sun, in winter it snows because the sun is in a different location.
<span>Pleural sac is a two
layered membrane formed when a serous membrane known as pleura folds back onto
itself. Thus, the pleura invest the lungs and line the walls of the thoracic
cavity. However, the potential volume of the thoracic cavity increases during
inhalation.</span>