- Grade 11 and 12 Mathematics (Moderator: geoffrey)
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- Grade 11 and 12 Mathematics (Moderator: geoffrey)
There are over 65,000 known species of protozoa. About 10,000 species are parasitic.
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.
Human kidneys will clean about 1 million gallons of blood in an average lifetime.
Prostaglandins were first isolated from human semen in Sweden in the 1930s. They were so named because the researcher thought that they came from the prostate gland. In fact, prostaglandins exist and are synthesized in almost every cell of the body.
Although puberty usually occurs in the early teenage years, the world's youngest parents were two Chinese children who had their first baby when they were 8 and 9 years of age.