(Q).
Q: Static friction acts on objects when they are resting on what? Read this paragraph and choose the correct option from the provided answers: Static friction acts on objects when they are resting on a surface. For example, if you are hiking in the woods, there is static friction between your shoes and the trail each time you put down your foot (see Figure below ). Without this static friction, your feet would slip out from under you, making it difficult to walk. In fact, that's exactly what happens if you try to walk on ice. That's because ice is very slippery and offers very little friction. Choices: - a single point - their laurels - a pool of water - a surface A:
(A).
a surface

(Q).
Q: What phenomenon involves the forcing of a substance into a cell against its concentration gradient? Read this paragraph and choose the correct option from the provided answers: During active transport, specialized integral membrane proteins recognize the substance and allows it access. Essentially this process is forcing a ion or molecule to cross the membrane when normally it would not. Moving a substance against its concentration gradient is known as primary active transport , and the proteins involved in it as "pumps". This process uses the energy of ATP. In secondary active transport , energy from an electrochemical gradient is used to transport substances. This process involves pore-forming proteins that form channels through the cell membrane. Choices: - active absorption - osmosis - secondary transport - primary active transport A:
(A).
primary active transport

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Q: What do you call a device that produces a very focused beam of visible light of just one wavelength and color? Read this paragraph and choose the correct option from the provided answers: Did you ever see a cat chase after a laser light, like the one in Figure below ? A laser is a device that produces a very focused beam of visible light of just one wavelength and color. Waves of laser light are synchronized so the crests and troughs of the waves line up. The diagram in Figure below shows why a beam of laser light is so focused compared with ordinary light from a flashlight. Choices: - optical diffuser - fusion relay - light meter - laser A:
(A).
laser