I got 13⁄13.
q11 (endangered species) was basically a guess. I thought that an extreme answer was more likely given how the quiz was set up to be counterintuitive/surprising. Also relevant: my sense is that we’ve done pretty well at protecting charismatic megafauna; the fact that I’ve heard about a particular species being at risk doesn’t provide much information either way about whether things have gotten worse for it (me hearing about it is related to things being bad for it, and it’s also related to successful efforts to protect it).
On q6 (age distribution of population increase) I figured that most people are age 15-74 and that group would increase roughly proportionally with the overall increase, which gives them the majority of the increase. The increase among the elderly will be disproportionately large, but that’s not enough for it to be the biggest in absolute terms since they’re only like 10% of the population.
On q7 (deaths from natural disaster) I wouldn’t have been surprised if the drop in death rate was balanced out by the increase in population, but I had an inkling that it was faster. And the tenor of the quiz was that the surprisingly good answer was correct, so if population growth had balanced it out then probably it would’ve asked about deaths per capita rather than total deaths.