Who has the greatest risk of having a child with Down syndrome?

Regarding the research on MDMA, which of the following statements is FALSE?

a. When a person stops taking MDMA, they tend to experience long-term feelings of anxiety and depression that can persist for months b. MDMA has been shown to increase sexual performance in both men and women. c. MDMA has been shown to intensify the impact of music for the user. d. MDMA users have sufferred fatal heat exhaustion and severe liver damage.

Much of the time, people engage in altruistic behavior because doing so makes them feel good. Is it correct to conclude, then, that altruistic acts are fundamentally selfish? Or should such acts be considered altruistic despite their seemingly selfish motives? What do the textbook authors conclude about this?

a. Such acts are best thought of as selfish (ego-driven). b. Such acts are best thought of as helpful (driven by social conscience). c. Such acts are best thought of as selfish AND helpful. Indeed, instead of pitting these drives against one another, the authors are positive about the evolution of these acts in general. d. Such acts are best thought of as selfish (ego-driven) UNLESS they involve clear self-sacrifices.