The base sequence in the DNA is A=T
G=C
This is B; false.
Europe is not located in the tropics. In fact, no European countries lie in the tropical region. Europe is located in the temperate climate zone.
Hormones -- such as melatonin and cortisol; the former signals the body to go to bed, while the latter signals for the sleeping person to wake up -- are created by physiological changes.
2NH3 is equivalent to N2 + H6 since the 2 at the beginning gets distributed to both atoms. Knowing this you can rewite the equation as
H2 + N2 = H6 + N2
The N2 can cancel out leaving
H2 = H6
You now have to ask ‘2 times what equals 6?’ The answer is obviously 3 at this point.
Answer: C. 3