Medulla oblongata in controling
a. heart beat
b. memory
c. movement
d. respiration

Heart beat (a)

Explanation:

The medulla, directly controls certain ANS( autonomic nervous system) responses, such as heart rate, breathing, blood vessel dilation, digestion, sneezing, swallowing and vomiting

the  frequency of a wave represents  the number of wavelengths that pass a specific point per second. the unit for  frequency  is hertz (hz).

happy to

pls mark as brainliest

answer : haversian

[explanation: -(compact bone is organized as parallel columns, known as haversian systems, which run lengthwise down the axis of long bones. these columns are composed of lamellae, concentric rings of bone, surrounding a central channel, or haversian canal, that contains the nerves, blood vessels, and lymphatic system of the bone)]