Crossing over happens in Meiosis 1 only. In Prophase 1 a cells chromatin (chromatin = chromosomes that have not condensed yet) condense and pair up forming homologous chromosomes (paired = XX (2 chromosomes together)). When this happens segments/ alleles of the chromosomes pairing up swap over. This creates genetic diversity as each chromosome is different, it has parts from its pair. This leaves every chromosome unique and individual.
I hope this helps, sorry some of the vocab is rather technical. By the way I would suggest watching the
'Crash Course: Meiosis' on YouTube, this really helped me when I was learning this topic. :D
Answer:
Homeostasis is the regulation of bodily functions to stay within a certain range.
Answer:
The World Health Organization defines health as "the state of complete physical, mental, and social wellbeing and not merely the absence of disease or infirmity." In either sense, health is a state of action that includes prevention, care, and individual responsibility to achieve optimal health.
Explanation:
Migration i think is the answer