Primary:
Grasshopper
Mouse
Grass
Secondary:
Hawk
Snake
Coyote
A cation is a positively charged ion.
An anion is a negatively charged ion.
If it's neutral, it's just an ion.
Explanation:
Tollens' reagent is prepared by using two-step process : -
Step 1:
Silver oxide is formed by mixing aqueous silver nitrate with base like sodium hydroxide. The reaction is shown below as:

Step 2
Ammonia solution is drop-wise added until all the silver oxide dissolves to form the reagent. The reaction is shown below as:

Answer: Option (4) is the correct answer.
Explanation:
A mixture is defined as a substance that contains two or more different substance that are physically mixed with each other.
If solute particles are evenly distributed in a solvent then it is known as a homogeneous mixture.
For example, salt dissolved in water is a homogeneous mixture.
If solute particles are unevenly distributed into the solvent then it is known as a heterogeneous mixture.
For example, sand in water is a heterogeneous mixture.
Thus, we can conclude that the statement a mixture must contain at least two different substances, is correct about mixtures.
Answer:
Described by a redox reaction below
Explanation:
Iron(III) oxide is an ionic compound, since it consists of a metal, iron, and a nonmetal, oxygen.
Ionic compounds are formed when metals lose their valence electrons in order to have an octet in their previous shell and donate them to nonmetal atoms, so that nonmetals fill their outer shell to have an octet.
As a result, positive ions (cations) and negative ions (anions) are formed. When iron reacts with oxygen, the following reaction takes place:

This is a redox (oxidation–reduction) reaction, since we have electron loss and gain. Four iron atoms lose a total of 12 electrons to obtain a +3 charge in the final compound, while 3 oxygen molecules gain these 12 electrons to become 6 oxide anions with a -2 charge.