Answer: The blanks can be correctly filled up with prophase I and metaphase II.
Explanation:
In females, finite number of oocytes are present since birth. The process of oogenesis initiate in embryonic stage only. However, oogonia divide and mature to form primary oocytes. These primary oocytes start meiotic division but arrest in prophase I stage before birth.
After a girl attains puberty, one primary oocyte resumes its division each month during a menstrual cycle. The primary oocyte divides to form secondary oocyte and polar body.
Polar bodies degenerate after completing meiosis II. However, secondary oocyte halts its division again at metaphase II until fertilization takes place. Once fertilization takes place it completes its meiosis II and results into mature ovum and polar body.
Answer:
Both physical and chemical weathering, along with erosion, can change Earth's surface as physical weathering allows breakdown of rock into smaller pieces, these pieces can be move from one place to another through water, wind or ice (erosion), and when the smaller pieces will settle down at a place, rain water can react with the soil or smaller rock pieces to form rock minerals.
For example: Running water, wind, and rapid heating/cooling allows the rocks to break down into smaller pieces or grains (physical weathering), then the small grains are transported and settled away from the source area through wind or river (erosion), and at the end the surface area exposed to air for chemical weathering.
It differs due to the life cycle of each tree, and the very specific way the trees go.