What is the labelled part 'x' in the above picture ?

What is the labelled part 'x' in- the above figure ?

Name the labelled part 'x' in the above picture.

A student prepared a model of alimentary canal just as shown below. Name the labelled part 'x' in the above picture.

Name the labelled part 'x' in the above figure.

Name the labelled part 'x' in the above figure.

Name the labelled part 'x' in the above figure.

Name the labelled part 'x' in the above figure.

Name the labelled part 'x' in the above figure.

Name the labelled part 'x' in the above figure.

Name the labelled part 'x' in the above figure.