Respuesta :
The answer for the first blank is “one”.
The answer for the second blank is “dominant”.
The answer for the third blank is “gain” of function.
Proto-oncogenes need or demand only "one" allele (gene copy or variant) to be altered in order to cause cancer (changes in the deoxyribonucleic acid or DNA). One allele is all that is required for a proto-oncogene to develop into an oncogene that causes cancer. Since only one allele (or gene copy) is required to create an oncogene that induces cellular transformation and resulting in cancer, it is referred to as a "dominant" mutation. This type of mutation causes a "gain" in function since the affected cells can now divide uncontrollably and serve a new purpose.
To learn more about Proto-oncogenes please visit here:
https://brainly.com/question/13252012
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