Oxidation number of Al(OH)4

Explanation:

The sum of all oxidation numbers in a neutral compound is zero. The sum of all oxidation numbers in a polyatomic (many-atom) ion is equal to the charge on the ion. The oxidation number of oxygen in a compound is usually –2. The oxidation state of hydrogen in a compound is usually +1.

The oxidation state of Al in Al(OH)

4

−

x+4(+1−2)=−1

∴x=+3

The oxidation state of Mn in MnO

2

y+2(−2)=0

∴y=+4

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c- cold periods in earth's history during which glaciers covered much of the surface.

explanation:

smooth muscle is composed of involuntary muscles found within the walls of organs and structures such as the esophagus, stomach, intestines, and blood vessels. those muscles push materials like food or blood through organs. unlike skeletal muscle, smooth muscle can never be under your control.