Earth's atmosphere has the lowest concentration of which of the following gases?
a. oxygen
b. nitrogen
c. carbon dioxide
d. argon

The correct answer is C - carbon dioxide.

The distribution of gases in the earth's atmosphere is as follows:

1. Nitrogen - 78  %

2. Oxygen - 21 %

3. Argon - 0.93 %

4. Carbon dioxide - 0.038%

Nitrogen, oxygen and argon are permanent gases whose percentage in  the atmosphere does not change from day to day.

Gases such as carbon dioxide, nitrous oxides, methane, and ozone are known as trace gases which make up 0.1% of the atmosphere.

endo:

regulates body hormones, aldosterone, vasopressin

neural:

signal, regulates body using electric signals, reflex

endo has to do with hormones; aldosterone and vasopressin are both hormones. i also had this question and got it right : d

i need an image of the diagram