3) Mendel arrived at his second law of inheritance when he studied a) one trait at a time
b) one generation at a time
c) two traits at a time
d) two generations at a time
4) Traits Mendel studied in pea plants included
a) flower color
b) stem length
c) seed color
d) all of the above

Which describes a difference between cephalopods and gastropods? cephalopods have a water vascular system, and gastropods have an open circulatory system. cephalopods live only in ocean environments, and gastropods live in a variety of environments. cephalopods have a simple nervous system, and gastropods have a complex nervous system. cephalopods are the largest group of mollusks, and gastropods are the smallest group of mollusks.