Did u fiure it out
?
nota clue
The layers on the top may be younger, while the bottom layers may be much older.
I think under the influence of Antidiuretic hormone (ADH), more concentrated urine is produced. Antidiuretic hormone also called vasopressin acts to maintain blood pressure, blood volume and tissue water content by controlling the amount of water and hence the concentration of urine excreted by the kidney increases. It also helps to control blood pressure by acting on the kidneys and the blood vessels.
Answer:
Genetic variation is caused by:
mutation
random mating between organisms
random fertilization
crossing over (or recombination) between
chromatids of homologous chromosomes during
meiosis
It's density is lower than water.