Explanation:
This much is undeniable. Based on the magnetic fingerprints locked into ancient rocks, we know that over the last 20 million years, magnetic north and south have flipped roughly every 200,000 to 300,000 years (this rate has not been constant over the planet's lifetime, though).
This could weaken Earth's protective magnetic field by up to 90% during a polar flip. Earth's magnetic field is what shields us from harmful space radiation which can damage cells, cause cancer, and fry electronic circuits and electrical grids.
D. wbc are not made in lymph nodes, wbcs are typically made in bone marrow and the thymus gland
The answer is b, decrease the oxygen gas pressure
