What is the bicoid protein?
A protein found in drosophillia that determines which end is the head and which end is the tail. When this protein is absent, a head does not develop and therefore the larvae dies. The protein is passed on from the mother's nurse cells. Since this protein is depended on the mother's cells, it is possible for the mother to be missing the bicoid protein and survive, but her offspring would not survive.
Convert this into exponential form: log(base 7)7=1
(d + 7)(d + 3)