A) Males gain energy more quickly by feeding at a faster rate and for longer periods of time than females.
B) Males that lose their major claw and then regenerate it incur significant production costs.
C) Males with their major claw have higher metabolic rates than males without their major claw.
D) Males with their major claw have lower endurance capacities than those without their major claw.

A) Bateman
B) Darwin
C) Tinbergen
D) Trivers

A) serves in male-male combat.
B) serves in mate attraction.
C) serves in both of the above functions.
D) is not involved in sexual selection, it's primary function being in feeding.