For example, of the two words lion and lioness, lion is unmarked for gender (it can denote either a male or female) whereas lioness is marked, since it denotes only females. b. Explicitly characterized by or having a particular linguistic feature.
20 Hertz to 20,000 Hertz is the frequency response range that a human can hear. So in answer to your question 20 Hertz would be the lowest pitch a human can hear.
This is because the sound waves are muffled by the floppy ear; still dogs hear a much higher and lower frequency than what we humans can. A dog has a hearing frequency of about 40 Hz to 60,000 Hz. The human hearing frequency is pegged at 20 Hz to 20,000Hz. However, dogs are known to be very sensitive to loud sounds. Loud noises that can be tolerated by humans would be extremely painful to dogs.