Answer:
Once the embryo sac has developed, pollination has occurred, and the pollen tube has grown into the ovary to make contact with the ovule, fertilization (fusion of egg and sperm) can occur.Typically, the pollen tube reaches the embryo sac via the micropyle (Greek, mikros + pyle = small opening), or opening, in the integuments of the ovule.. There, it discharges its sperm into the embry
Explanation:
The pollen tube enters into the ovule, through the micropyle. Inside the embryo sac, the tip of the pollen tube ruptures and the 2 male gametes are set free near the egg apparatus. Inside the embryo sac, one of the 2 male gametes fuses with the egg nucleus and forms a diploid zygote. This process is called syngamy or true fertilisation.
Answer:
On January 22, 2001, EPA adopted a new standard for arsenic in drinking water of 0.01 mg/l or 10 parts per billion (ppb), replacing the old standard of 50 ppb. Water systems had to meet the new standard by January 23, 2006.
Explanation:
Nutrients enter a cell up the concentration gradient by the process of active transport.
