Answer:
Air mass can be described as the volume of air present and the temperature of that mass of air.
Polar air masses are cold. They have less moisture content. The temperature of Maritime Polar air mass ranges from above freezing to below 70 degrees F.
Tropical air masses can be described as air masses that are warm and have a high moisture content. Temperature ranges between 70 degrees F to 90 degrees F.
It's called a tectonic shift.
These plates are always shifting, and they can either grind in opposite directions, pull away from one another, or collide to create a fault-line.
Producers are green plants or photosynthetic organisms that are the basis for the other living parts of any ecosystem. Producers need to have access to light to produce food. Few producers will be found deep below a lakes surface simply because the deeper you travel under water the less light penetrates those deeper layers.