What is the difference between section and part?

Here's the basic idea.

part - a general term. eg I can use my hands to break a part off a loaf of bread.

section - refers to a part that is more clearly defined.

eg it's easy to divide an orange into sections.

eg sub-headings are often used to divide a business report into sections.

Ali, forgive me for mentioning this. Politeness is an important part of speaking English.

It would be nice if you said please and/or thank you in these queries that you are asking us to help you with.

Thank you, Clive
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Thank you:)

You're very welcome.Emotion: smile

Clive, certainly you must know the roots of english and its origins as a language of pirates. It takes and plunders. It is certainly not polite.
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In most modern contexts I am familiar with, taking and plundering is somewhat frowned upon.