A. It has mass.
Air is matter, and can't be seen thus not all matter can be seen.
Any liquid or gaseous is matter (water, air, etc.)
Since it can be liquid or gaseous it doesn't have to maintain it's shape and size to be matter.
Answer:
All of the options are correct.
Arboviral diseases are arthropod borne, they can produce central nervous system illnesses, transmitted by mosquito bites and also produce acute self limiting fevers.
Explanation: Arboviruses are viruses that are harboured by arthropods which includes mosquitoes, they have the capacity to cause illnesses which are acute and self limiting(it has the ability to resolve on its own without treatment). It has also been found to cause illnesses to the central nervous system(the brain and the spinal cord).
Answer:
Winding mills are made on hills because of air flow and currents.
Explanation:
Winding mills capture wind to turn blades and produce energy. In order to do so, it needs winds! Strong winds, in order to turn the blades. You will notice that if you ever scale a mountain or go higher, it starts to become windier/the wind blows harder.
If the wind mills are placed higher, it can capture these windier conditions, thus moving the wind blades to produce energy. The higher the hill, the stronger the wind current, the more energy it produces.
