Can someone confirm my answers? This is a new topic that I just learned in school and I'm a bit confused about it. So I'm not exactly sure about my answers. And this stuff is going to be on my midterm.

What actions take place during G1?
A) the cell doubles its nuclear content
B) the cell doubes its cytoplasmic content
C) a and b
D) the cell takes in food and grows to double its size

I put D.

After brain cells grow in G1, they enter G0 ..
A) so that brain cells do not replicate
B) so that a brain tumor does not form
C) a and b
D) brain cell do not enter G0

I put A, but my gut is telling me its C.

If spindle fibers fragmented, chromosomes ..
A) would not line up at the equator
B) would not separate evenly into the two poles
C) a and b
D) nothing would happen, they're not vital to cell division

I put C.

If G1 did not take place ..
A) chromosomes would not replicate
B) chromosomes would not line up at the equator
C) daughter cells would never go into mitosis
D) daughter cells would not grow

I put D.

It might help if you explain what G1 is. We are short-handed in the biology department here.