What Does the Moon Smell Like?: 151 Astounding Science Quizzes by Eva Everything Read Free Book Online Page A

dance floor on the head of an average pin. A typical human cell is about 10 micrometres across — that’s just ten millionths of a metre, or about one 2,500th of an inch. Can you say microscopic? Here’s another way to imagine how truly tiny typical human cells are. Say your hair is of average thickness, with each strand about 100 micrometres across. Ten cells could hang out, side by side, across one of your head hairs. If you’ve got coarse hair, five cell buddies could join them.
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    Forensics 101
    Criminologists use DNA to identify both victims and Q
    perpetrators. If you’ve watched forensics shows on TV, you’ve seen the investigators collecting blood samples at the gory crime scene. The DNA is extracted from CELLULAR
    the blood and analyzed at the state of the art lab in record time, and by the end of the hour, science has triumphed over crime, thanks to the DNA in the blood BEINGS
    sample. So, have you learned anything about forensic science by watching TV shows? Let’s find out.
    Which blood cells are used for DNA analysis?
    a) platelets
    b) red blood cells
    c) white blood cells
    d) all of the above
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    Forensics 101
    Which blood cells are used for DNA analysis?
    A
    a) platelets
    b) red blood cells
    c) white blood cells
    CELLULAR
    d) all of the above
    BEINGS
    CORRECT ANSWER:
    c) white blood cells
    From watching forensics shows, you might get the impression that red blood cells are used in DNA analysis. But they can’t be used, and neither can other blood cells, called platelets, because these types of cells don’t contain DNA. White blood cells do contain DNA, and they’re the ones that are analyzed in real forensics labs.
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    How Human Are You?
    One hundred trillion. That’s an estimate of how many Q
    cells make up an adult human body. Hard to imagine, isn’t it? When you look in the mirror, you see a flesh-and-blood human being, not a huge collection of CELLULAR
    cells. Based on what you can see, you might assume that all your cells are true human cells. Ahhh, but are they really?
    BEINGS
    What percentage of the cells in your body are true human cells?
    a) 10%
    b) 30%
    c) 60%
    d) 90%
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    How Human Are You?
    What percentage of the cells in your body are true A
    human cells?
    a) 10%
    b) 30%
    CELLULAR
    c) 60%
    d) 90%
    BEINGS
    CORRECT ANSWER:
    a) 10%
    Only about 10 trillion of those 100 trillion cells are true human cells. Brace yourself if you’re squeamish, because this means that there are close to 90 trillion bacteria crawling around in your body! Most of them make a living in your gut. Your gastrointestinal tract is sterile when you’re born, but by the time you’re just one month old, about 500 species of bacteria have moved in and set up permanent colonies. It’s a good thing too, because without them, we wouldn’t be able to digest our food.
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    ONE OF A KIND: PLATYPUS
    The Platypus’ Secret Weapon
    Close relatives of today’s platypus were already on the Q
    scene when the dinosaurs ruled the earth. Fast-
    forward 110 million years to 1799, when the first Australian platypus pelt arrives in England. No one can believe it’s for real. It looks like a duck’s bill has been sewn onto a beaver-like body. It has to be a hoax. The claim that the bizarre-looking creature is an egg-laying mammal doesn’t fly either. Most scientists ridicule the poor platypus and insist the pelt is a fake. Can you imagine how they would have reacted if they’d been told about the platypus’ secret weapon?
    What is the platypus’ secret weapon?
    a) a honk so shrill it can shatter glass
    b) skunk-like scent glands under its tail
    c) toxic saliva
    d) venomous spurs on its ankles
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    The Platypus’ Secret Weapon
    What is the platypus’ secret weapon?
    A
    a) a honk so