Answer:
The drum skin oscillates 20 times per second
Explanation:
The frequency of a note is dependent on the mechanical activities that occur when it is produced. A drum is beaten in this case. The oscillation of the drum skin transfers sound waves to the air particles which move at the same frequency before reaching our ears.
If the frequency of the sound wave is 20 Hz this means that the wave is oscillating 20 times in one second. For the drum to produce such a sound, the skin must have been oscillating at the same frequency of 20 oscillations per second too.
Answer:
An autotroph is a cell that is capable of producing its own energy using photosynthesis or, less commonly, chemosynthesis.
A heterotroph is a cell that must consume its energy from external sources, for instance, hunting for prey or eating autotrophs.
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It becomes D. Groundwater
Answer:
the difference is that permanent gases have larger residence times and Variable gases have shorter residence times
