The term migration fits the definition of a species brought into an ecosystem where it doesn't naturally occur
Can be methan.
Due to the decomposing process, methan is released into the air and it can be collected in some special tanks
The nucleus holds strands of DNA that stores the genetic material
The answer is DNA
Oncogenes result from turning on, or activating proto oncogenes. Proto oncogenes are genes that code for positive cell cycle regulators, so proto oncogenes code for proteins that turn on cell division. Proto oncogenes are normal genes, but when they are mutated, they become oncogenes. Oncogenes are expressed too much, which makes them turn on cell division too much, which is cancer.