A Topic sentence is normally the first or second sentence, though it can be located anywhere in the paragraph. It regularly introduces the topic or gives the most useful information in the paragraph. It makes a statement (or asks a question) that the rest of the paragraph explains or supports with examplesof what the topic sentence has said.
Examples:
"I'm going to talk about dogs."
"Today I'm going to share with you a few things you most likely did not know about dogs."
A topic sentence is a sentence that give you kind of a hint of what your story is going to be about. It doesn't give what your story is about, it just gives a little clue.
A cause makes an effect happen, and an effect comes about as a result of a cause.
A sentence that notes an effect that resulted from that cause
The topic sentence, the body with supporting sentences, and the clincher sentence
To support your answer. It shows the reader why you chose to write about this.
Ernest Henry Shackleton was known as a brave explorer who was also cautious and wise when he traveled.
Rephrasing a thesis.