Boiling Water is a physical change. When water gets to a certain temperature, it's boiling point starts.
Answer:

Explanation:

The incomplete combustion of alkanes, and other fuels actually, happens when there is a limited supply of oxygen. Instead of the fuel burning completely to produce carbon dioxide, it produces carbon monoxide instead.
This gas is harmful to jumans because it combines with haemoglobin in lood and takes up space that belongs to oxygen which can lead to suffocation or even death
Answer: The molecular formula will be 
Explanation:
Molecular formula is the chemical formula which depicts the actual number of atoms of each element present in the compound.
Empirical formula is the simplest chemical formula which depicts the whole number of atoms of each element present in the compound.
Empirical weight of
is
Molecular mass of compound is = 132 g
Now we have to calculate the molecular formula.
The molecular formula will be=
Climate is considered an abiotic limiting factor because it is non living . hope this helped :))
I don't know why I am answering this question but assuming C-13 has a natural abundance of 1.07%:
(1.6000x10^4)(0.0107) = 171.2 = 171 atoms of C-13