You divide the number of chromosomes in half, just like humans. So the female zygote has 28 chromosomes and the male sperm have 28 chromosomes. This way each set of chromosomes contributes the same amount to each sex cell.
Very simple. You can't renew it. Which one of the options seem like you cannot renew the resource in a reasonable amount of time?<span />
B) genome would be your answer.
Microorganisms such as bacteria can be removed by disinfection. Certauns substances called biocides are addes to water to make it pure. Purification can also be done by UV-light .