Would it be lack of water and food?
Answer: protons and neutrons.
The nucleus is made up of 3 subatomic particles that are protons,neutrons and electrons.
General notation of an element is 
where, X is the Element, A is the Atomic Mass and Z is the Atomic Number
If we know the number of protons we can easily find out the atomic number of any element because Atomic Number = Number of protons in an element.
And in addition if we know the number of neutrons we can easily find out the atomic mass of an element because
Atomic Mass = (Number of protons) + (Number of neutrons)
If we get to know the atomic number and atomic mass, we can easily tell what element is it by looking from the periodic table.
Answer:
<h2>377 kPa</h2>
Explanation:
The original pressure can be found by using the formula for Boyle's law which is

where
P1 is the initial pressure
P2 is the final pressure
V1 is the initial volume
V2 is the final volume
Since we're finding the original pressure

150 kPa = 150,000 Pa
We have

We have the final answer as
<h3>377 kPa</h3>
Hope this helps you