Answer:
Oiling is done on a regular basis to sewing Machine because in the machine there are lots of machinery parts i.e. wheels and axels, etc. which are in continuous use and they possess so much frictional force between them that wear tear may be observed in those parts.
The appropriate answer is d. recording and studying seismic waves. Seismic waves behave differently as the enter the different layers of the Earth. Scientists used seismic or earthquake waves to determine the different layers of the Earth. The behaviour of the waves as they move through the layers helped scientists identify the boundaries and the state of each layer; solid or liquid.
<span>A cloud collapses to form a star and disk. Planets form from this disk.
According to our current understanding, a star and its planets form out of
a collapsing cloud of dust and gas within a larger cloud called a nebula
.his dense, hot core becomes the kernel of a new star.
Hoped this helped :D
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