Groups PCA in 3D

Move the points so that they are in three separated groups. How do the points appear when n = 1 and they are projected to PC1, PC2, or PC3?

What is the variance and Explained variance ratio when points are projected onto PC1, PC2, and PC3?

Switch the number of principal components to 2. Which combination of two principal components best preserves the three groups?

What does the explained variance ratio seem to indicate about the projected points?