A geneticist wants to isolate mutants in mice that are defective in nucleotide-excision repair (NER) but is unable to do biochemical analysis on the NER system so must use some other method to identify putative NER mutations. Which of the following would most likely be useful in identifying NER mutations in mice?1. Identifying possible NER mutants by their progeny consisting of a reduced number of females with a normal number of males when they are crossed to normal mice
2. Identifying possible NER mutants by their high spontaneous mutation rates for base-pair substitution and frameshift mutations
3. Identifying possible NER mutants by their increased susceptibility to UV irradiation compared to normal mice
4. Identifying possible NER mutants by their high rate of cytosine deaminations compared to normal mice
5. All of the above would be characteristic of NER nutants

the scientific method.

interphase

the period of cell growth when the cell synthesizes new molecules and organelles. the cell is not dividing and it constitutes the majority of the time spent in the cell cycle

prophase

changes occur in the nucleus and cytoplasm. the chromatin condenses to form structures (sister chromatids) visible with a light microscope and the mitotic spindle begins to form, but the nucleus is still in tact

prometaphase

the nuclear envelope fragments and the spindle microtubules attach to the kinetochores of the sister chromatids

metaphase

all the cell's duplicated chromosomes are lined up at an imaginary plane equidistant between the poles of the mitotic spindle

anaphase

begins when sister chromatids separate from each other and ending when a complete set of daughter chromosomes arrives at each of the two poles of the cell

telophase

the daughter nuclei form at the two poles of a cell

cytokinesis

the division of a cytoplasm to form two separate daughter cells. usually occurs during telophase during mitosis. this and mitosis make up to mitotic (m) phase of the cell cycle

d. changes in climate and historical records

hope this