as the light intensity is increased the rate of photosynthesis is:. (A) increase. (b) decreased (C) same (D) none of these

Not 100% sure, however I think that the correct answer is A (increased).

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.