EN
We prove that if f:𝕀 → 𝕀 is Darboux and has a point of prime period different from $2^i$, i = 0,1,..., then the entropy of f is positive. On the other hand, for every set A ⊂ ℕ with 1 ∈ A there is an almost continuous (in the sense of Stallings) function f:𝕀 → 𝕀 with positive entropy for which the set Per(f) of prime periods of all periodic points is equal to A.