Answer the following question given this paragraph: Each section contains a liquid crystal sample with a different liquid crystalline range. The section whose liquid crystalline range corresponds to the temperature of the body becomes translucent (here shown in green), indicating the temperature. We also see the effect of liquid crystals in nature. Iridescent green beetles, known as jewel beetles, change color because of the light-reflecting properties of the cells that make up their external skeletons, not because of light absorption from their pigment. The cells form helices with a structure like those found in cholesteric liquid crystals. When the pitch of the helix is close to the wavelength of visible light, the cells reflect light with wavelengths that lead to brilliant metallic colors. Because a color change occurs depending on a person's angle of view, researchers in New Zealand are studying the beetles to develop a thin material that can be used as a currency security measure. The automobile industry is also interested in exploring such materials for use in paints that would change color at different viewing angles. With only molecular structure as a guide, one cannot precisely predict which of the various liquid crystalline phases a given compound will actually form. One can, however, identify molecules containing the kinds of structural features that tend to result in liquid crystalline behavior, as demonstrated in Example 11. Q: Iridescent green beetles, known as jewel beetles, change color because of the light-reflecting properties of the cells that make up this? Choices: - their hairs - their wings - their scales - their external skeleton A:
their external skeleton
(Question)
Answer the following question given this paragraph: Salts Recall that salts are formed when ions form ionic bonds. In these reactions, one atom gives up one or more electrons, and thus becomes positively charged, whereas the other accepts one or more electrons and becomes negatively charged. You can now define a salt as a substance that, when dissolved in water, dissociates into ions other than H+ or OH. This fact is important in distinguishing salts from acids and bases, discussed next. A typical salt, NaCl, dissociates completely in water (Figure 2.15). The positive and negative regions on the water molecule (the hydrogen and oxygen ends respectively) attract the negative chloride and positive sodium ions, pulling them away from each other. Again, whereas nonpolar and polar covalently bonded compounds break apart into molecules in solution, salts dissociate into ions. These ions are electrolytes; they are capable of conducting an electrical current in solution. This property is critical to the function of ions in transmitting nerve impulses and prompting muscle contraction. Q: What substances, which are distinct from acids and bases, form when ions form ionic bonds? Choices: - oils - vitamins - water molecules - salts A:
(Answer)
salts
Ques: Answer the following question given this paragraph: A tight junction is a watertight seal between two adjacent animal cells (Figure 3.17b). Proteins hold the cells tightly against each other. This tight adhesion prevents materials from leaking between the cells. Tight junctions are typically found in the epithelial tissue that lines internal organs and cavities, and composes most of the skin. For example, the tight junctions of the epithelial cells lining the urinary bladder prevent urine from leaking into the extracellular space. Also found only in animal cells are desmosomes, which act like spot welds between adjacent epithelial cells (Figure 3.17c). They keep cells together in a sheet-like formation in organs and tissues that stretch, like the skin, heart, and muscles. Gap junctions in animal cells are like plasmodesmata in plant cells in that they are channels between adjacent cells that allow for the transport of ions, nutrients, and other substances that enable cells to communicate (Figure 3.17d). Structurally, however, gap junctions and plasmodesmata differ. Q: What is the term for a watertight seal between two adjacent animal cells? Choices: - cell membrane - cell wall - placental barrier - tight junction A:
Ans: tight junction
(Q).
Answer the following question given this paragraph: When current keeps reversing direction, it is called alternating current (AC) . You can see how it works in the two diagrams below. The current that comes from a power plant and supplies electricity to homes and businesses is alternating current. The current changes direction 60 times per second. It happens so quickly that the light bulb doesn't have a chance to stop glowing when the reversals occur. Q: What is it called when currents keep reversing direction? Choices: - circle current - emitting current - stream current - alternating current A:
(A).
alternating current
Ques:Answer the following question given this paragraph: If all three bulbs are set a full intensity, the person sees __________. Q: Chewing insects such as dragonflies and grasshoppers have how many sets of jaws? Choices: - one - four - three - two A:

Ans:two
Ques:Answer the following question given this paragraph: The stomach is a sac-like organ at the end of the esophagus. It has thick muscular walls that contract and relax to squeeze and mix food. This helps break the food into smaller pieces. It also helps mix the food with enzymes and other secretions in the stomach. For example, the stomach secretes the enzyme pepsin, which helps digest proteins. Q: What is a sac-like organ at the end of the esophagus? Choices: - appendix - larynx - spleen - the stomach A:

Ans:
the stomach