The chart below depicts the different phases of embryo development for a human. Label each image in the space provided.

It shows that the experiment is designed properly.

☆ionisation energy increases across a period from na -> ar☆ionisation energy decreases down a group from li -> fr☆ionic radius decreases across a period from na -> cl☆ionic radius increases down a groupfrom f -> ii hope it clarifies your doubts

The answer for this is a