Answer: I'm in no way like an expert but I've heard water goes from an elevated area to a lower area. So it should be arrows that start at a more elevated to less elevated. Like white to brown, and orange to yellow, and stuff like that. I hope that helped? Anyway, have a lovely day!
Explanation:
Answer:
liver and esophagus.
Explanation:
Kidneys are part of the endocrine system, trachea and bronchi are part of the respiratory system
Answer: 72 grams of
are needed to completely burn 19.7 g 
Explanation:
According to avogadro's law, 1 mole of every substance weighs equal to molecular mass and contains avogadro's number
of particles.
To calculate the number of moles, we use the equation:

Putting in the values we get:


According to stoichiometry:
1 mole of
requires 5 moles of oxygen
0.45 moles of
require=
moles of oxygen
Mass of 
72 grams of
are needed to completely burn 19.7 g 
H2O is a compound. So it's second one.
You spell Chlorine wrong but the process is called electrolysis