1. Which of the following statements are true in Euclidean geometry and which of the following statements are true in neutral geometry? Write one or two sentences to justify your choices for each. (a) The exterior angle theorem. (b) The Pythagorean theorem. (c) A Saccheri quadrilateral exists. (d) If there exists a triangle having an angle sum of less than 180, then no rectangle exists. (e) There is a triangle with angle sum less than 180