I can use this background: In practice, the diameter of the aperture is chosen based on the focal length of the lens, the diameter and quality of the input beam, and its wavelength (longer wavelengths require larger apertures). If the hole is too small, the beam quality is greatly improved but the power is greatly reduced. If the hole is too large, the beam quality may not be improved as much as desired.  The size of aperture that can be used also depends on the size and quality of the optics. To use a very small pinhole, one must use a focusing lens with a low f-number, and ideally the lens should not add significant aberrations to the beam. The design of such a lens becomes increasingly more difficult as the f-number decreases.  Now, I have a new situation: David needs to purchase a camera for his photography class. He went to the local consumer electronics store to find himself a good camera. Two cameras caught his eye, camera A and camera B. Camera A had a very small pinhole, but camera B had larger aperture. David needs to decide which camera should he buy.  Answer this question please: Which camera would have lower f-number focusing lens, camera A or camera B?
----
Answer: camera A


I can use this background: There is growing concern regarding the use of pesticides in agriculture. Therefore, many of the current commercial applications of modern biotechnology in agriculture are focused on reducing the dependence of farmers on these chemicals. For example, Bacillus thuringiensis (Bt) is a soil bacterium that produces a protein that can act as an insecticide, known as the Bt toxin . But it is a naturally occurring protein, not a foreign chemical. Could this protein be used in crops instead of pesticides? Traditionally, an insecticidal spray has been produced from these bacteria. As a spray, the Bt toxin is in an inactive state and requires digestion by an insect to become active and have any effect. Crop plants have now been engineered to contain and express the genes for the Bt toxin, which they produce in its active form. When an insect ingests the transgenic crop, it stops feeding and soon thereafter dies as a result of the Bt toxin binding to its gut wall. Bt corn is now commercially available in a number of countries to control corn borer (an insect like a moth or butterfly), which is otherwise controlled by insecticidal spraying.  Now, I have a new situation: Two farmers tried different methods of growing their crops. Nate used pesticides, while his buddy Don used bacterium that produces a toxin instead. Don was happy with the results.  Answer this question please: Which farmer used a bacterium that produces Bt toxin?
----
Answer: Don


I can use this background: Solar radiation (or sunlight) is the energy Earth receives from the Sun. Earth also emits radiation back into space, but at longer wavelengths that we cannot see. Part of the incoming and emitted radiation is absorbed or reflected by the atmosphere. In May 2017, glints of light, seen as twinkling from an orbiting satellite a million miles away, were found to be reflected light from ice crystals in the atmosphere.  Now, I have a new situation: Mark was studying the effect of Sun's radiations on Earth. To that end, he studied Sun's radiations, which he labeled as rad A. Then he studied Earth's radiations, which he labeled as rad B. He also learned that longer wavelength radiations would produce heat.  Answer this question please: Which radiation is not visible, rad A or rad B?
----
Answer:
rad B