Answer: C. By changing the genetic makeup of the crops.
Explanation: It's correct because this was one of my questions for Study Island and I put in this answer which was right!
Your answer will be "Trial and Error" hope this helps
D) Silicon Contents is correct
Polygenic inheritance. The characteristics of a person aren't controlled completely by a single gene, but rather several genes that generally only make a small contribution to how the child turns out in the outcome. At one point there was a study that showed over 400 genes were linked to height, so imagine any other characteristics of a person. Environmental effects also serve a large purpose in how a child is to turn out. These children may all be growing up in the same environment, however that's not to say they all grow up the same. They could all be treated the same way and react differently to it, this counts both for physical and mental traits. All human's features such as eye colors, hair color and height are determined by several different genes. As an example, there are around 2 major eye color genes, however there are also around 14 different genes that actually contribute in determining a person's exact eye color. Some are bound to look the same, as they have the same parents, however, just because they have the same parents doesn't mean they all will look exactly alike.
Humans have caused quokka populations to decrease due to animal cruelty. Humans have also introduced predators to quokkas, such as dogs and cats.
Hope this helped!