input: OPTIONS:
- break down food
- secrete stomach acid
- stop digestion
- keep food moving Now, answer this question: Answer the following question given this paragraph: Organs of the GI tract are covered by muscles that contract to keep food moving along. A series of involuntary muscle contractions moves rapidly along the tract, like a wave travelling through a spring toy. The muscle contractions are called peristalsis. The diagram in Figure below shows how peristalsis works. Q: What do the muscles of the gastrointestinal tract do? A:
A:
output: keep food moving

Answer the following question given this paragraph: Unlike ethers, esters have a carbonyl group. Unlike carboxylic acids, esters have no acidic hydrogen atom; they have a hydrocarbon group in its place. Q: Carboxylic acids have an acidic hydrogen atom, but esters do not. what do esters have in place of an acidic hydrogen atom? A:

OPTIONS:
- synthesis group
- carbonation group
- crystallization group
- hydrocarbon group

Answer: hydrocarbon group

Problem: OPTIONS:
- legs
- head
- neck
- backbone or a spinal column
Q: Answer the following question given this paragraph: The first vertebrates evolved about 550 million years ago. The evolution of amphibians, reptiles, mammals, and birds occurred over the next 400 million years. The first vertebrates were ectotherms; endothermy evolved later. Modern fish, amphibians, and reptiles are ectotherms. Modern birds and mammals are endotherms. Q: Vertebrates differ from invertebrates because they lack this? A:
Answer: backbone or a spinal column

Problem:OPTIONS:
- interposition
- disapprobation
- misappropriation
- disproportion

Answer the following question given this paragraph: Disproportion is a type of redox reaction in which the same substance is both oxidized and reduced. Identify the element that is disproportionating and indicate the initial and final oxidation numbers of that element. 2CuCl(aq) CuCl2(aq) + Cu(s) Saylor URL: http://www. saylor. org/books. Q: What term describes a type of redox reaction in which the same substance is both oxidized and reduced? A:
****
A: disproportion

Answer the following question given this paragraph: Unlike the sponges which evolved prior to cnidarians, the cnidarians are made up of true tissues. The inside of a cnidarian is called the gastrovascular cavity , a large space that helps the organism digest and move nutrients around the body. The cnidarians also have nerve tissue organized into a net-like structure, known as a nerve-net, with connected nerve cells dispersed throughout the body. Cnidarians do not have true organs, however. Q: What is a large space that helps the organism digest & move nutrients around the cnidarian body? A:
OPTIONS:
- thorax
- abdominal wall
- vacuole
- gastrovascular cavity
gastrovascular cavity

Answer the following question given this paragraph: Electron Microscopes In contrast to light microscopes, electron microscopes use a beam of electrons instead of a beam of light. Not only does this allow for higher magnification and, thus, more detail (Figure 3.3), it also provides higher resolving power. Preparation of a specimen for viewing under an electron microscope will kill it; therefore, live cells cannot be viewed using this type of microscopy. In addition, the electron beam moves best in a vacuum, making it impossible to view living materials. In a scanning electron microscope, a beam of electrons moves back and forth across a cell's surface, rendering the details of cell surface characteristics by reflection. Cells and other structures are usually coated with a metal like gold. In a transmission electron microscope, the electron beam is transmitted through the cell and provides details of a cell's internal structures. As you might imagine, electron microscopes are significantly more bulky and expensive than are light microscopes. Q: What powerful microscopes use a beam of subatomic particles instead of a beam of light? A:
OPTIONS:
- complex microscopes
- scientific microscopes
- nuclear microscopes
- electron microscopes

Answer:
electron microscopes