Me ! i will give

a person with trisomy 21 has an extra copy of chromosome 21. what happened during meiosis that caused the person to get three, instead of two, copies of chromosome 21?

binary fission
crossing-over
genetic recombination
nondisjunction

Will mark brainliest! 1.) jan’s sister and mother have both had breast cancer. she is wondering if she should undergo genetic testing to check for a mutation of the brca1 gene. a mutation in the brca1 gene is commonly associated with, but not guaranteed to cause, breast cancer. the presence of a mutation increases a patient’s chances of getting breast cancer to about 85 percent, compared to a 13 percent risk in the general population. costs may vary, but most labs charge patients or their insurance companies less than $3,000 to sequence the brca1 to look for mutations. do you think that jan should undergo genetic sequencing? explain your answer. (2 points) what are potential pros and cons of having such tests done? (5 points) describe how the availability of genetic sequencing can affect the frequency of genetic diseases in individuals and populations. (3 points) 2.) scientists have developed genetically engineered plants that are pest-resistant. by adding genes to the plant’s dna, they become toxic to insects (but not to plants or animals). this means that these plants may not need to be sprayed with pesticides to ward off the insects. would you be willing to eat these genetically altered crops? explain your answer. (5 points) what are some possible impacts (positive or negative) of this genetically engineered plant on the environment, society, and individuals? (5 points)