Khan Academy is great! Also, Alison (it's a website) has some free courses as well.
Answer:
used to observe small objects, even cells
Explanation:
The image of an object is magnified through at least one lens in the microscope.
C.)
.............................................. if not im sorry
That right there is a line graph
Depending on baseline oxygen saturation and the pathological condition of the lungs, risks associated with altitude exposure include profound hypoxemia, pulmonary hypertension, disordered ventilatory control, impaired respiratory muscle function, and sleep‐disordered breathing.
