Final answer:
In monogamous systems, paired males and paired females can both engage in extra-pair copulation. Polyandry, where one female mates with multiple males, is less common than polygyny due to higher female investment in offspring. Monogamy can be advantageous for species where male assistance increases offspring survival. option c.
Step-by-step explanation:
In a monogamous system, both paired males and paired females are capable of participating in extra-pair copulation (EPC). While monogamy involves a social and genetic bond between one male and one female for at least one breeding season, EPC refers to mating that occurs outside the primary mating pair. Each sex may have different motivations for engaging in EPC: For males, the opportunity to spread their genes further, and for females, the chance to improve the genetic quality of their offspring.
The term polyandry comes from the Greek words for 'many' and 'man,' indicating a mating system where one female mates with many males, as seen in some seahorse and pipefish species. This is in contrast to polygyny, where one male mates with several females. Polyandrous systems are relatively rare, especially compared to polygynous ones, mostly due to the higher energy requirements females typically invest in offspring production and development.
One advantage of monogamous relationships in animal species could be the male-assistance hypothesis, where males providing help in guarding and rearing young may see more and healthier offspring survive.