Oxygen<span> is a </span>chemical element<span> having a symbol </span>O<span> and having an </span>atomic number<span> 8.
Oxygen is a pure substance , and it is not a mixture or solution, Niether it is a compound ... Instead , it forms chemical compounds by reacting with other elements.
So , according to above explanation ,
A. A pure substance , is the correct answer.</span>
Simple machines help reduce the amount of work being done, as they help by using a simple function. One disadvantage is that they do not help completely.
Scale is defined as the measurement of unit ranges, that has been corresponds to the measurements.
The units for the measurement of temperature are given as:

<h3>Which scale is used?</h3>
The scale used for the measurement of the freezing is the temperature scale. The temperature is measured in the units of Kelvin, Fahrenheit , and Celsius.
The unit scale for the measurement of freezing of water are
- Freezes at 32 - In the Fahrenheit scale
- Freezes at 0 - In the Celsius scale
- Freezes at 273 - In the Kelvin scale
Learn more about measurement scale, here:
brainly.com/question/1152255
The term Rutherford gave to the positively charged particles in the nucleus of an atom was/is Proton.
Hope this helps!
<span>Most of earths carbon is in the atmosphere in the form of a gas?</span>