Answer:
Scientist come to know about the land feel by various measures such as quantity of methane gas, quantity of radioactive materials, etc. They collect data from a particular area and checks it whether it is under critical range or not.
Explanation:
Land-filling is a process by which all the waste which is solid is buried under the ground. It is also a type of land pollution. It degrades the land quality. The land is no more fertile to grow crops. some of the waste are also radioactive which harmful effect the animals and plant living in that area. It also tends to have the humans living nearby that area. this area is also capable of creating methane gas which is very explosive in nature.
Scientist plays an important role for finding out the critical condition of land. They also have instrument which are very helpful for finding out the critical range of the radioactive materials.
The two events that occur when gravity causes a nebula to collapse into itself are:
A. Nuclear fusion start.
B. A new star forms.
Explanation:
- Nebula are giant clouds of dust and gases.
- These clouds are considered as progenitors of stars and planets.
- The gravitational pull within these giant clouds result these large masses to collapse towards their centre.
- The gravitational collapse results in tremendous rise in temperature till a point where nuclear fusion begin .
- The stars are born out of such mechanism and act as a source of heat and light in universe.
Models are simplified representations of of different complex systems. They also help to study very small or large objects.
Option B, D and E.
Explanation:
Models are very simplified representations of complex systems and organs or structures which are prepared to study those systems by scientists and normal people easily. Many structures of human body like cells or some tissues are very small in structure or microscopic in nature. So studying them are very hard without specific instruments which are not always available. Thus models are made to easily study those structures by scientists and even normal people and students.
Answer: fewer areas have fertile soil reducing crop production
Explanation:
I j got it right
Answer: Friction
Explanation: Sir Isaac Newton, a soccer ball on the grass will stay where it is unless acted on by a force.
