Final answer:
Parent-offspring conflicts arise when resources given to one offspring reduce the parent's potential to have more offspring due to the inverse relationship between parental care and fecundity.
Step-by-step explanation:
The interests of parents and their offspring are generally compatible; however, parent-offspring conflicts may arise when the accumulation of resources by one offspring reduces the overall fecundity of its parents. This occurs because resources allocated to one offspring can no longer be used to produce or care for additional offspring, which decreases the parent's potential reproductive capacity. Parental care and fecundity have an inverse relationship, where species that provide extensive care to their offspring typically have fewer offspring. This is due to the energy needed for parental care that could alternatively be used to produce more offspring. Therefore, conflicts are most likely to arise in scenario 3), where one offspring's resource demand negatively impacts the parent's ability to reproduce further.