Answer:
<em>O</em><em>r</em><em>g</em><em>a</em><em>n</em><em>i</em><em>s</em><em>m</em><em> </em><em>,</em><em> </em><em>P</em><em>o</em><em>p</em><em>u</em><em>l</em><em>a</em><em>t</em><em>i</em><em>o</em><em>n</em><em> </em><em>,</em><em> </em><em>C</em><em>o</em><em>m</em><em>m</em><em>u</em><em>n</em><em>i</em><em>t</em><em>y</em><em> </em><em>,</em><em> </em><em>E</em><em>c</em><em>o</em><em>s</em><em>y</em><em>s</em><em>t</em><em>e</em><em>m</em><em> </em><em>.</em>
Explanation:
<u>Organism</u> is one type of species .
<u>Population</u> is a group of same species living together .
<u>Community</u> is a group of different species living together .
<u>Ecosystem</u> is a large group of community of species and its environment consisting of biotic and abiotic factor .
Answer: 
Explanation:
According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.
The balanced equation will be:

Through Air sounds travels approximately 343 meters/second. Why the difference? Because the closer together the molecules in a substance are, the faster sound will travel through that medium.
Answer:
I think its iron(II) oxide
Explanation:
The substance is black but when it's mixed with water it turns green solution so when mixed with sodium Hydroxide it turns green
Answer:The heat source for our planet is the sun. Energy from the sun is transferred through space and through the earth's atmosphere to the earth's surface.
Explanation: