$(a)$ Which of the following frequencies are audible to human ears: $2 \, Hz$,$5 \, Hz$,$20 \, Hz$,$200 \, Hz$,$2000 \, Hz$?
$(b)$ How are moths of certain families able to escape capture?

(A) The audible range for human ears is $20 \, Hz$ to $20,000 \, Hz$. Therefore,the frequencies $20 \, Hz$,$200 \, Hz$,and $2000 \, Hz$ are audible to human ears.
$(b)$ Moths of certain families have the ability to hear the high-frequency ultrasonic waves emitted by bats. When they detect these sounds,they perform evasive maneuvers or drop to the ground to avoid being captured by the bats. Additionally,some moths have evolved structures that do not reflect the ultrasounds sent towards them by bats,effectively making them 'invisible' to the bat's echolocation.