The sister is 4<em>n</em><em> </em>yrs old.
That is because 4 times <em>n</em><em> </em>is 4<em>n</em><em>.</em>
<span>To provide consistent ways to identify and classify organisms as they are being studied.</span>
Answer:

Step-by-step explanation:
We can apply the distributive property then combine like terms for a simpler equation.

Hope this helped!
The 1, 2, 3 I’m not sure bout the 4th one