Please help me solve this

Some mining processes involve removal of large areas of earths surface in the mined region this practice causes severe environmental damage by allowing which natural process to accelerate in the affected areas? a.precipitation b.erosion c.migration d.condensation

Which is an important function of normal flora? a. aid with bone marrow production. b. crowd out pathogenic bacteria. c. destroy digestive track pathogens. d. manufacture iron in the bloodstream.

Dna and rna share a number of similarities,but they also differ in certain aspects of their structure. wich nitrogenous base is found in rna but is not found in dna