Question

Is #4 correct, if not what is

Answer 1

A number to the 0 power is 1, so your answer is correct.

y to the 4th power is equal to A because when you combine the two, you add their exponents.

 It is also equal to B. y to the 6th power divided by y to the 4th power because when you divide two exponents, you just subtract. So that means it is equal to D.

Answer 2

Number 4 is correct a^0=1 for all real number a
number 5
y^2(y^2=y^(2+2)=y^4 correct
y^6/y^2=y^(6-2)=y^4 correct
y^0=1 false
y^9/y^5=y^(9-5)=y^4 correct
y^4(y^1)=y^(4+1)=y^5 false