Answer:
E. Frequency
E. Semicircular canals
D. A circadian rhythm
D. Fovea
Endocrine system.
Step-by-step explanation:
Pitch, in speech, the relative highness or lowness of a tone as perceived by the ear, which depends on the number of vibrations per second produced by the vocal cords ie frequency related scales.
The ear is a sensory organ that picks up sound waves, allowing us to hear. It is also essential to our sense of balance: the organ of balance (the vestibular system) is found inside the inner ear. The vestibule is the region of the inner ear where the semicircular canals converge, close to the cochlea (the hearing organ).
A circadian rhythm is the 24-hour cycle that regulates the timing of processes like eating, sleeping, and temperature. This ensures that there is a periodicity with necessary biological processes.
The area of greatest visual acuity is situated inside the macula called fovea. It has the maximum number of rods responsible for vision.
The endocrine system is a chemical messenger system comprising feedback loops of the hormones released by internal glands of an organism directly into the circulatory system, regulating distant target organs.