Answer:
b. amount of energy available as fuel for the body
In order to conduct a research you should have an dependent variable, independent variable and the control variable. so in order to study phototropism, then you should need sun light and the growth of the plant and you must have a control that why you need a dark room.
ANSWER
The correct answer is A
<u>EXPLANATION</u>
From the equation 
<u>L.H.S.</u>
Fe = 1
O =2
<u> R.H.S</u>
Fe =2
O =3
Now, let try to balance the oxygen atoms first,
To do this, we know the Least Common Multiples of 2 and 3 is 6
To get 6 atoms of oxygen at L.H.S multiply 2 by 3 and on the R.H.S, multiply 3 by 2
L.H.S.
R.H.S
This means that, 3 should be in front of
at the L.H.S and 2 should come before
in the R.H.S of the equation
Now, we have
L.H.S.
Fe = 1
O = 6
<u>R.H.S</u>
Fe =4
O =6
The equation is still not balanced since Fe is not balance
The Least Common Multiple of 1 and 4 is 4
Which means that we need to multiply 1 by 4 at the L.H.S and 4 by 1 at the R.H.S
L.H.S.
R.H.S
We now, have
<u>L.H.S. </u>
Fe= 4
O=6
<u>R.H.S</u>
Fe =4
O=6
Hence the balanced equation is

Answer:
a. ΔG was negative.
Explanation:
The answer is a. ΔG was negative because, for a biochemical reaction to occur and provide energy for cellular metabolism, the Gibbs free energy ΔG = ΔH - TΔS < 0 , for spontaneity. If all terms on the right were to be negative, then ΔG = -ΔH - (-TΔS) = TΔS - ΔH and would only be less than zero if the absolute value of ΔH > absolute value of TΔS. If ΔG was positive as in C, the reaction would not be spontaneous and energy would have to be put into the biochemical reaction for it to occur. If all terms on the right were positive, then, ΔG = ΔH - TΔS < 0 when TΔS > ΔH , else ΔG > 0 and energy would have to be put into the biochemical reaction for it to occur, so its not spontaneous.
I’m not sure but what i know is the u need to find the problem by steps