During prophase, which of the following events
take place? check all that apply.
spindle fibers form.
dna condenses into chromosomes.
chromosomes move to opposite ends of the
cell.
nuclear membrane begins to re-form.

Spindle fibers form.

DNA condenses into chromosomes.

Explanation:

Prophase is the first stage of mitosis. Mitosis produces 2 daughter cells from a parental cell.

Spindle fibers form - this is true. During prophase, the mitotic spindle forms. Later during mitosis the spindle attaches to the centromere of chromosomes and pulls them to opposite ends of the cell prior to division

DNA condenses into chromosomes.  - this is true. In the nucleus during interphase, the DNA is relatively loosely compacted. However, prior to division, the DNA is condensed into structures called chromosomes which are then paired up and distributed to the daughter cell.

Chromosomes move to opposite ends of the  cell.  - this is false. This happens during anaphase

Nuclear membrane begins to re-form. - this is false. This happens during telophase.

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer