A plant that is too short may not be able to compete with other plants for sunlight. However, extremely tall plants may be very susceptible to wind damage. Combined, these two selection pressures are an example of which type of selection

Ryan is deciding between attending western state university and eastern state university. he cannot attend both universities simultaneously. both are fine universities, but the reputation of western is slightly higher, as is the tuition. let mu subscript upper e and mu subscript upper w be ryan's marginal utilities from attending eastern and western state universities respectively and upper p subscript upper e and upper p subscript upper w be the prices of attending eastern and western state universities. using the rule of consumer optimum, ryan will decide to attend eastern state university, if mue/pe exceeds muw/pw attend eastern state university if mue/pe is less than muw/pw attend western state university, if pe/mue< pw/muw attend western state university, since it gives him more utility.