Athesis statement is a sentence that

Claims what you are going to talk about

A thesis statement clearly identifies the topic being discussed, it should only cover what is being discussed in the paper, and is written for a specific audience. Your thesis statement belongs at the end of your first paragraph, also known as your introduction.

basically a sentace that states the main idea of your essay

the abdomen (less formally called the belly, stomach, tummy or midriff) constitutes the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. the region occupied by the abdomen is termed the abdominal cavity. the stomach secretes acid and enzymes that digest food. ridges of muscle tissue called rugae line the stomach. the stomach muscles contract periodically, churning food to enhance digestion. the pyloric sphincter is a muscular valve that opens to allow food to pass from the stomach to the small intestine.