Which type of reaction is typified by containing a single element and a single compound in both the reactants and products?
a. decomposition
b. double replacement
c. combustion
d. single replacement

A. Decomposition.

Explanation: This is a reaction when a compound breaks down to form two and/or more easier substances. When this reaction turns into a single replacement, only one element is placed there for basically filling in for another element that is in a compound that is similar to the one before. That being said about the substances, this reaction is a big part because it takes away substances, then replaces them with newer and similar ones each time it has completed it's work. It's just a long train of work for Decomposition.

I hope this helps you!

a: 45.9 meters

b: 4.29 seconds

step-by-step explanation:

a: h(t)=1/2(-9.8)(3)^2+0(3)+90

h(t)=-4.9(3)^2+90

h(t)=-44.1+90

h(t)=45.9 meters

b: 0=1/2(-9.8)(t^2)+0t+90

0=-4.9t^2+90

-90=-4.9t^2

18.37=t^2

t=4.29 seconds

in the second question, the numbers aren't exact, but they're a close approximation.