Which type of unconformity exists between two horizontal rock layers if the older rock is much older than the younger rock?
a. disconformity
b. nonconformity
c. angular unconformity

The type of unconformity exists between two horizontal rock layers if the older rock is much older than the younger rock is : Angular Unconformity.
The sedimentary in this interaction created some sort of angular discordance with the overlying horizontal layers

Amath expression is a collection of one or more terms, which are separated by the signs ( + , - , x , / ).example :   8+b8+b  or  a−3a−3in algebra, an equation is a mathematical statement with two expressions where, each expression is separated by an equal (=) sign. variables can be present on both the sides of the equality (=) sign and we use letters to denote such variables.example 1:   x=4+2x=4+2  , [here, we can observe that the variable is present only on one side of the equation].example 2:   2x+3=x+42x+3=x+4  , [here, we can observe that the variables are present on both side of the equation].