Exercise 2 solution

1. Genetics of the bees: only indirectly, by which bees you keep (my opinion; the article does not say how).
2. Congestion of the brood nest: plausibly, by giving room (my opinion; the article only names it as a factor).
3. Too few empty combs for nectar and honey: plausibly, by providing empty comb (this follows directly from the wording of the factor).
4. Inadequate ventilation: plausibly, through hive design and set-up (my opinion).
5. An old queen: yes, queens can be replaced (the earlier chapters say beekeepers often replace queens every year or two).
6. Warming weather: no.

The article lists the factors but says nothing about how a beekeeper should act on them, so every "yes" above is partly my reading.