A.   Food availability

B.   All of these statements are correct

C.   The number of males who are available for mating

D.   The number of gametes females can produce

A.   All of these statements are correct

B.   Gaining more access to resources by cooperating with other females

C.   Gaining more access to resources by being successful in competition with other females

D.   Finding the optimal amount of care to invest in offspring

A.   Allomaternal care is more likely

B.   Males invest more in care of offspring than females do

C.   The more females invest in the care of their offspring, the less time and resources they have to devote to future offspring

A.   favors traits that make individuals more attractive to the opposite sex

B.   favors traits that make individuals more successful in competition for access to mates

C.   Both of these responses are correct

A.   How long a monogamous pair bond lasts

B.   Reproductive success

C.   Tail length

A.   In one-male/multi-female groups

B.   In species that have enduring pair bonds

C.   False; males never invest in offspring

A.   In one-male/multi-female groups

B.   In multi-male/multi-female groups

C.   In polyandrous groups

A.   Variation in reproductive success is the highest for males

B.   Monogamy is common

C.   Humans are present

A.   Occurs because nursing requires an enormous amount of calories

B.   All of these statements are correct

C.   Temporary

D.   Ends when offspring are weaned

A.   When a male increases in rank

B.   During the rainy season

C.   When a new female enters a group