Answer the following question given this paragraph: Earth's magnetic poles have switched places repeatedly in the past. As you can see in the Figure below , each time the switch occurred, Earth's magnetic field was reversed. The magnetic field is the region around a magnet over which it exerts magnetic force. We think of today's magnetic field direction as "normal," but that's only because it's what we're used to. You can watch a simulation of a magnetic field reversal at this URL: http://www. pbs. org/wgbh/nova/earth/when-our-magnetic-field-flips. html. Q: The earth's magnetic poles have done what repeatedly in the past? Choices: - rotated - stayed the same - demagnetized - switched places A:
switched places

Answer the following question given this paragraph: Epithelial tissue from epithelium. Below this is dermis, thicker and with blood vessels. Two specialized epithelia: pseudostratified transitional Pseudostratified epithelia lines the trachea (where it is ciliated)and the male urethra (where it is non ciliated), looks stratified but not. Transitional epithelia found only in bladder and urinary system. As it stretches it appears to go from 6 to 3 cell layers deep. Glandular epithelia (gland: group of cells that excretes something. mostly derived from epithelium. Glands are classified into endocrine and exocrine by where they excrete. Endocrine glands secrete hormones into the blood without use of ducts. Exocrine glands secrete onto the body surface or into a cavity, thru a duct. Exocrine substances include sweat, mucous, oil, and saliva. An exocrine gland is the liver, which secretes bile. Q: Is sweat an exocrine or endocrine substance? Choices: - neither - both - exocrine - exocrine A:
exocrine

Answer the following question given this paragraph: The structure of a chloroplast is shown in Figure below . The chloroplast is surrounded by two membranes. Inside the chloroplast are stacks of flattened sacs of membrane, called thylakoids . The thylakoids contain chlorophyll. Surrounding the thylakoids is a space called the stroma . The stroma is filled with watery ("aqueous") fluid. Q: Thylakoids in a chloroplast contain what plant pigment? Choices: - melanin - dye - ultramarine - chlorophyll A:
chlorophyll

Answer the following question given this paragraph: Some rocks contain little compasses too! As lava cools, tiny iron-rich crystals line up with Earth's magnetic field. Anywhere lavas have cooled, these magnetite crystals point to the magnetic poles. The little magnets point to where the north pole was when the lava cooled. Scientists can use this to figure out where the continents were at that time. This evidence clearly shows that the continents have moved. Q: As lava cools, tiny iron-rich crystals line up with earth's what? Choices: - gravitational field - oceans - molecular field - magnetic field A:
magnetic field