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Egg cells are about the size of a grain of sand. They are formed inside of a female's ovaries before she is even born.
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.
Giardia is one of the most common intestinal parasites worldwide, and infects up to 20% of the world population, mostly in poorer countries with inadequate sanitation. Infections are most common in children, though chronic Giardia is more common in adults.
Bacteria have flourished on the earth for over three billion years. They were the first life forms on the planet.
Blood is approximately twice as thick as water because of the cells and other components found in it.