Answer:
A cell's plasma membrane, also known as the cell membrane, provides protection. It also maintains a constant atmosphere within the cell, and the membrane serves a variety of purposes. The first is to transport nutrients into the cell, and the second is to transport toxic compounds out
Explanation:
Answer:
The correct answer is B.
Explanation:
The molecule of water has 2 atoms of hydrogen and 1 atom of oxygen.
The ratio of masses are given as:

This illustrates the law of definite proportions which is also known as law of constant compositions .
The law states that 'the elements combining to form compound always combine in a fixed ratio by their mass.'
Whereas :
Law of multiple proportion states that when two elements combine with each other to form more than one compounds , the mass of one element with respect to the fixed mass of another element are in ratio of small whole numbers.
Law of conservation of mass states that mass can neither be created nor be destroyed but it can only be transformed from one form to another form.
In a balanced chemical reaction ,total mass on the reactant side must be equal to the total mass on the product side.
Law of conservation of energy states that energy can neither be created nor be destroyed but it can only be transformed from one form to another form.

Now, balance the equation:


in gaseous state exist as a diatomic molecule.
The one that happens when the atoms of a substance are regrouped is : a new substance is formed.
After atoms being regrouped the molecules of the original substance will be different and the substance will have different properties from those of the reactans
Answer:
1)Around 450 B.C., the Greek philosopher Democritus introduced the idea of the atom.
2)All matter is made of atoms, Atoms are indivisible and indestructible.Compounds are formed by a combination of two or more different kinds of atoms, A chemical reaction is a rearrangement of atoms.
3)B
Explanation: