<u>Answer</u>: c. a and b
Trees play vital roles in the production of oxygen as well as the fixation of carbon from 
. As trees use nitrogen, phosphorus and water as nutrients for growth, their diminishing numbers would change the balance between these three elements significantly.
Thus, during rains, the water level will rise much faster and higher in the absence of trees. These could possibly lead to increasing cases of devastating landslides.
the most important to the survival of the ecosystem is sunlight
Genetic engineering:Pros: produces more food, makes organisms more fit, increases knowledge and knowledge is good.Cons: Some say it's: playing God, dangerous due to recombination of DNA, contamination of the gene pool, big pharma could take over the "means of production".
In-vitro fertilization: Pros: Allows people who couldn't have children to do so, increases knowledge and knowledge is good.Cons: Expensive (really expensive), can lead to overpopulation (minor), can be done irresponsibly (minor as everything can be).
