The correct answer is: A. A change in a cell's genetic material.
Mutations occur in DNA as a result of mistakes during the DNA replication (when repair mechanisms don’t fix it) or as the result of environmental factors (e.g. UV light). Mutations can have positive impact, by increasing the genetic variation or can have negative effect, causing the diseases or cancer.
Answer: <u>Option D point source pollution
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Explanation: The pollutants which can be tracked, from the source of origin are termed as point source pollution. This can be water source, air or even light or noise pollution. The pollutants are easily detected being released from the source of pollution. Whereas the non-point source of pollution are those which are indirect sources and they carry off the pollutants which lie on the way, like runoff water carrying the pesticides from the agricultural land. Runoff and waste are examples of non-point sources of pollution. Thus, option A and C are incorrect answers.
It is important that the cell membrane contains openings into the cell because different ions and molecules enter and exit the cell through pores (membrane channels) located in the membrane.
