<span>the formation of a gas
</span>
the plants would grow and reproduce working together forming nutrients from their dropped leaves / branches etc causing insects to come along and do the same along with animals and a keystone species to form a revolving ecosystem continuing an energy moving process
<h2>
contains both covalent and ionic bonds.</h2>
Explanation:
A covalent bond is formed when an element shares its valence electron with another element. This bond is formed between two non metals.
An ionic bond is formed when an element completely transfers its valence electron to another element. The element which donates the electron is known as electropositive element or the metal and the element which accepts the electrons is known as electronegative element or non metal.
a.
contain covalent bonds as they are made up of non metals only.
b.
contain ionic bonds as they are made up of sodium metal and fluorine non metal.
c.
contain covalent bonds as they are made up of non metals only.
d.
contain ionic bonds between
and
and covalent between N and H in 
Learn more about ionic and covalent bonds
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brainly.com/question/2877158
This problem is providing the chemical reaction whereby barium nitride reacts with water to produce barium hydroxide and ammonia, so the number of moles of barium nitride are required in order to produce 8.3 moles of ammonia. It asks for us to evaluate the student's setup, so we conclude the answer is C. "1 mol of NH3 should be replaced with 2 mol of NH3", according to:
<h3>Mole ratios:</h3>
In chemistry, stoichiometric calculations are used to figure out the moles or mass of a substance, given information about another one in the reaction. In this case, for the given chemical equation:

We evidence a 1:2 mole ratio of barium nitride to ammonia, for that reason, the student's setup:

Is incorrect, because the ammonia must be accompanied by a 2 rather than the 1 it is given there:

Thereby, the correct answer is C. "1 mol of NH3 should be replaced with 2 mol of NH3"
Learn more about mole ratios: brainly.com/question/15288923