Which equation is correct regarding the measure of ∠1?
m∠1 = (a – c)
m∠1 = (a + c)
m∠1 = (b – d)
m∠1 = (b + d)

The fact that the earth goes through natural cycles for example the ice age some scientists belive that it is just another cycle

Answer is b)eutrophication occurs when excess nutrients are present in aquatic ecosystems, resulting in the increased production of plant life and the subsequent decrease in the oxygen levels of the watereutrophication occurs when there are excess nutrients in a body of water. this results in plants having more food and reproducing  more, sometimes leading to more aquatic animal life as well. ultimately, this can reduce the oxygen level in the ecosystem.