The protostome and deuterostome are discussed below in a number of ways. Identify the option that includes the correct statements about protostomes and deuterostomes. 
P. In protostomes, the first opening in the embryo becomes the mouth. 
Q. In deuterostomes, the first opening in the embryo becomes the anus, and the mouth develops later. 
R. The majority of protostomes are vertebrates. 
S. Deuterostomes contains both invertebrates and vertebrates.