What did leonardo observe verrocchio create for his patrons?

The correct answer is the following.

Leonardo observed the work of Verrocchio the religious motives in his paintings and the sculptures he created for many clients. He made a lot of works for Piero and Lorenzo de' Medici. Leonardo, as an apprentice of Verrocchio, learned the designs and ways to do business of his teacher.

Andrea del Verrocchio (1435-1488) was a famous sculpture that created beautiful pieces of work in the painting too. Probably, his most famous creation is in Venice, Italy. It is the equestrian statue of Bartolomeo Colleoni.