Which statement describes the distinction among ephemeral, intermittent, and perennial streams, and why the distinction matters in ecological assessments?

• A. Ephemeral streams flow year-round; intermittent flow occurs seasonally; perennial streams flow only after rainfall.
• B. Ephemeral streams flow only after rainfall; intermittent flow occurs seasonally; perennial streams flow year-round; The distinction affects habitat availability, species presence, and regulatory protections.
• C. Ephemeral streams have no flow; intermittent streams have continuous flow; perennial streams dry during drought.
• D. Ephemeral streams flow year-round; intermittent flow occurs seasonally; perennial streams flow year-round; The distinctions do not affect assessments.

Answer: (B)