Answer: water
For many centuries, it was considered that there were only three states of matter: solid, liquid and gas (the three that are present and stable in our world). And water is the substance that best represents them, because it is the only one that exists naturally in the three states.
Explanation: Matter can exist in one of three main states: solid, liquid, or gas.
Solid matter is composed of tightly packed particles. ...
Liquid matter is made of more loosely packed particles. ...
Gaseous matter is composed of particles packed so loosely that it has neither a defined shape nor a defined volume.
Answer:
.
Explanation:
Given that
MM''= a cos(fL)
We know that all trigonometric function are dimensional less.So fL should be dimension less quantity.
Property Dimension
Length L
Mass M
Force 
Acceleration 
Velocity 
Torque 
Time 
So in the given question ,dimension of L is L so the dimension of f will become .
C.
They broke down materials by chemical means
Answer:
Explanation:
Earth is considered a closed system because only energy, not matter, is exchanged. A closed system like Earth can be easily represented by a sealed jar. When the lid is sealed, matter like air or water can neither enter nor exit the jar. If you placed that same jar in a 100-degree oven, the air inside the jar would eventually increase in temperature to 100 degrees, representing an exchange of energy known as heat.
Answer:
P and Q
Q and R
Explanation:
To begin, we must bear in mind the meaning of isotope.
Isotopes are atoms having the same atomic number (i.e proton) but different mass number due to the difference in the neutron number present in the atoms involved.
Thus, we shall write out the number of protons, neutrons and electrons present in the model given above. This is given:
Model P:
Proton = 12
Neutron = 13
Electron = 13
Model Q:
Proton = 12
Neutron = 12
Electron = 13
Model R:
Proton = 12
Neutron = 13
Electron = 12
From the above data, we can say that:
1. P and Q are isotope since they have different Neutron number.
2. P and R are not isotope since they have the same Neutron number.
3. Q and R are isotope since they have different Neutron number.
