Using an analogy of a cyclist to describe light dependent reactions, what do the downhill sections represent

Which sequence represents a cross section of the bilayera hydrophilic head, hydrophobic tail, hydrophobic tail, hydrophilic headb hydrophobic tail, hydrophilic head, hydrophobic tail, hydrophilic headc hydrophobic head, hydrophilic tail. hydrophilic tail, hydrophobic headd hydrophilic tail, hydrophobic head, hydrophobic head, hydrophilic tail

Spring tides, when the high tides are at their highest and low tides at their lowest. what is it about these positions that causes these high and low tides?

What is used to keep track of the gamates and possible offsprings combination