Question
What must happen before meiosis can begin
DNA replication must come first before meiosis to happen.Previous to replication, a germ cell contains two copies of each chromosome, a maternal copy. and a paternal copy.
I'm not sure if I will answer the question you asked, as I many have interpreted it incorrectly. In natural selection, there must be variance in the gene pool, the total frequency of alleles in a population. Now, one of the organisms may have a gene that somehow helps them survive from the selective force much better compared to the others. If this does happen, over time the gene pool will narrow down to become just the genes of that organism that survived better in the first place because the rest would be taken care of by the selective force. So, the alleles and trait come from the first organisms that had the advantage over the others of its species.
Answer:
Petroleum gas is mainly C3 and C4 based (propane and butane), whilst natural gas is predominantly C1 and C2 (methane and ethane). Petroleum gas is generally produced via the cracking of naphtha, which is one of the components separated during crude oil refining.
Explanation:
South America, Brazil, Canada, And Hawaii
Hope this helps :)
Among others, both plants and animals need oxygen and water. They also both need space and air.
