If you could focus all of the money and effort that people donate to advance causes to a single end, what would you pick?

Reproductive rights/control. Birth control and full access to all the available options to all.
Could help with- Slowing the spread of AIDS, poverty, hunger, environmental impact of over population, education, abuse…

National Debt.

“That’s easy. I’d just slide that wad over to my father. He is like one of the top brokers in the state.” Heathers

I guess my final answer is whatever agency I can find to best effect birth control across the world.

Nature preservation.

Funding for scientific research on problems that would improve the quality of life for most of the people in the world.

@Dr_Lawrence Too broad, too broad.

A top notch education for every child in the world, pre-school through college. In addition to the usual academics/arts/health, I’d also like to focus on: critical thinking, compassion, problem solving, and cultural education. All schools would also have a ‘free meals’ program for those in need of it… breakfast and lunch, every day.

The way I see it, being fed meets a huge need today, and being really well educated will solve a whole host of problems down the line.

One specific cause? I think I would pick stem cell research.

Commercial magnetic/intertial confinement fusion reactors.

Solar power. Alternative fuel sources.

Stroke and cardiovascular diseases research, the leading causes of death throughout most of the world.

I’m with @augustlan Education for all children of all genders in every place on earth.

My single end would be the world depicted in the Star Trek universe. Which includes most what was mentioned above. And a few extra treats. Like holosuits and food replicators.