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Only 12 hours after an egg cell is fertilized by a sperm cell, the egg cell starts to divide. As it continues to divide, it moves along the fallopian tube toward the uterus at about 1 inch per day.
Signs of depression include feeling sad most of the time for 2 weeks or longer; loss of interest in things normally enjoyed; lack of energy; sleep and appetite disturbances; weight changes; feelings of hopelessness, helplessness, or worthlessness; an inability to make decisions; and thoughts of death and suicide.
The average office desk has 400 times more bacteria on it than a toilet.
On average, the stomach produces 2 L of hydrochloric acid per day.
Adult head lice are gray, about ? inch long, and often have a tiny dot on their backs. A female can lay between 50 and 150 eggs within the several weeks that she is alive. They feed on human blood.
![Fibroid tumors, or leiomyomas. Fibroids develop from the uterus to form a variety of hard, round ben](https://biology-forums.com/gallery/47/medium_14755_26_10_12_5_31_31_9713214.jpeg)
![A the subfossil lemurs of Madagascar filled a variety of niches occupied elsewhere by monkeys, as sh](https://biology-forums.com/gallery/47/medium_274477_04_02_15_12_29_04_205931233.jpeg)