bcd said:
*Identify the industrial source of ethene from the catalytic cracking of some of the fractions from the refining of petroleum.
To what extent do we need to identify the process of catalytic cracking?
BCD!
That would be a one-marker, where the question would be extremely similar to:
Identify the industrial source of ethene: _____________________________
Which you will answer with "catalytic cracking".
If they ask you what catalytic cracking is, then go on to talk about zeolites, give equations, and so on.