you need degrees
To be a chemical engineer you have to have knowledge in chemistry and physics. You'll need to have your degree and sometimes further education is needed.
No Maths is needed to become an engineer.
In general, in order to become a petroleum engineer, you will need to have an engineering degree. You will also need to have done a masters in petroleum engineering.
there are specialised chemical engineering course throughout the world, most of them are given at university level
You should not have to take biology to become an aerospace engineer.
Usually math and science
There is a lot of education that is needed to become a toxicologist. You need many medical education courses in school
to study about codes
none
nothing
Chemical engineers can do things ranging from design equipment to supervising manufacturing activities. To be a chemical engineer you need knowledge in chemistry, mathematics, and mechanical and electrical engineering.
a bachelors degree is needed for all entry levels.