False
crossing over occurs in prophase 1 of meiosis 1. The significance of this crossing over is to ensure cell differentiation. If this occurred in prophase two it means the cells in meiosis 1 will be identical.
Experimental technique I believe
Answer: high-energy primary cosmic-ray particles interact with air nuclei high in the atmosphere, initiating a cascade of secondary interactions that ultimately yield a shower of electrons, and photons that reach ground level.
Explanation:
