Differentiate sandy beach and dune ecosystems and explain how each supports different fauna.

• A. Beaches experience frequent moisture and salinity fluctuations with shifting substrates; dunes are stabilized by vegetation and host specialized insects, birds, and terrestrial fauna.
• B. Beaches are stable environments; dunes are barren with no vegetation.
• C. Beaches have constant fresh water; dunes host only birds.
• D. Beaches are inland; dunes are offshore.

Answer: (A)