Here is the difference: an indirect question is a sentence that reports a question and ends with a period rather than a question mark. A direct questions is a sentence that asks a question and ends with a question mark.
Indirect speech, also called reported speech or indirect discourse, is a means of expressing the content of statements, questions or other utterances, without quoting them explicitly as is done in direct speech. For example, He said "I'm coming" is direct speech, whereas He said he was coming is indirect speech. Indirect speech should not be confused with indirect speech acts.
In terms of grammar, indirect speech often makes use of certain syntactic structures such as content clauses ("that" clauses, such as (that) he was coming), and sometimes infinitive phrases. References to questions in indirect speech frequently take the form of interrogative content clauses, also called indirect questions (such as whether he was coming).
An informal fallacy is an argument whose stated premises fail to support its proposed conclusion. The problem with an informal fallacy often stems from a flaw in reasoning that renders the conclusion unpersuasive. In contrast to a formal fallacy of deduction, the error is not merely a flaw in logic.
A rhetorical question is a figure of speech in the form of a question that is asked in order to make a point. The question, a rhetorical device, is posed not to elicit a specific answer, but rather to encourage the listener to consider a message or viewpoint. Though classically stated as a proper question, such a device may be posed declaratively but implying a question, and therefore may not always require a question mark when written. Though a rhetorical question does not require a direct answer, in many cases it may be intended to start a discussion or at least draw an acknowledgement that the listener understands the intended message.
A common example is the question "Can't you do anything right?". This question, when posed, is intended not to ask about the listener's abilities, but rather to insinuate a lack of the listener's abilities.
The question mark (?; also known as an interrogation point, interrogation mark, question point, query, or eroteme), is a punctuation mark that replaces the full stop (period) at the end of an interrogative sentence in English and many other languages. The question mark is not used for indirect questions. The question mark character is also often used in place of missing or unknown data. In Unicode, it is encoded at U+003F ? question mark (HTML: