Why doesn’t a stable ecosystem have more tertiary consumers than primary consumers?

The boiling point of propanoic acid is higher than that of 1-butanol because: propanoic acid has a higher molecular weight than 1-butanol. propanoic acid is more soluble in water than 1-butanol. propanoic acid is a better hydrogen bond donor than 1-butanol. propanoic acid forms hydrogen bonded dimers and 1-butanol does not. 1-butanol forms hydrogen bonded dimers and propanoic acid does not.

Avariable that is not being directly tested during an experiment should be changed varied experimented controlled

In a ball-and-stick molecular model, what do the sticks represent?