A would be the best answer hope this helps
It's basically a wave that moves back and forth at regular speed through matter. because of that it transfers energy through a medium (matter). however the movement of the wave is limited because of this but it can still move over long distances. so because of this these types of waves don't move far from their original point or Equilibrium position. in short think of throwing a pebble into water and seeing the little ripples from it, that's a mechanical wave.
When a cell is in G2 phase, it has already doubled in S phase its DNA, meaning that for each chromosome we have two chromatids -> 2n(number of chromosomes)×2(number of chromatids per chromosome)=number of chromatids.
If 160 is the number of chromatids on G2 phase of a chicken cell, it means that the cell has 80 chromosomes (2n), and after meiosis, process to form a sperm cell, will only have 40 chromosomes (n).
