Final answer:
Successful negotiation of the genital stage is marked by the development of mature sexual interests and the ability to establish healthy, intimate relationships. This reflects an individual's capacity to redirect sexual desires towards acceptable partners, emerging from a successful resolution of earlier psychosexual stages and experiences during puberty.
Step-by-step explanation:
The given statement suggests that neighboring plant species generally have a positive effect on the target species at low-elevation sites (helped) and a negative effect at high-elevation sites (hurt). Therefore, the correct option is b. helped; hurt.
During puberty, significant changes occur including the development of secondary sex characteristics and increased hormone levels, facilitating sexual maturation. Integral to the conceptual understanding of the genital stage and Freud's psychosexual development theory is the recognition of this stage as a time for adolescents to form romantic relationships, often experienced for the first time in late adolescence.