Q: Where do cells come from? Read this paragraph and choose the correct option from the provided answers: No matter what the cell, all cells come from preexisting cells through the process of cell division. This is one of the core concepts of the Cell Theory. The cell may be the simplest bacterium or a complex muscle, bone, or blood cell. The cell may comprise the whole organism, or be just one cell of trillions. But whatever type of cell it is, it comes from a preexisting cell. And the new cell is genetically identical to its parent cell - that is, it has exactly the same DNA. Choices: - sexual reproduction - mutations - nuclear fission - preexisting cells A:
preexisting cells

Q: What are the gas giants mostly made of . Read this paragraph and choose the correct option from the provided answers: The gas giants are mostly made of hydrogen and helium. These are the same elements that make up most of the Sun. Astronomers think that most of the nebula was hydrogen and helium. The inner planets lost these very light gases. Their gravity was too low to keep them and they floated away into space. The Sun and the outer planets had enough gravity to keep the hydrogen and helium. Choices: - calcium and helium - nitrogen and helium - hydrogen and carbon - hydrogen and helium A:
hydrogen and helium

Q: Q: How are valuable metabolites recovered? Read this paragraph and choose the correct option from the provided answers: Flame Cells of Planaria and Nephridia of Worms As multi-cellular systems evolved to have organ systems that divided the metabolic needs of the body, individual organs evolved to perform the excretory function. Planaria are flatworms that live in fresh water. Their excretory system consists of two tubules connected to a highly branched duct system. The cells in the tubules are called flame cells (or protonephridia) because they have a cluster of cilia that looks like a flickering flame when viewed under the microscope, as illustrated in Figure 41.10a. The cilia propel waste matter down the tubules and out of the body through excretory pores that open on the body surface; cilia also draw water from the interstitial fluid, allowing for filtration. Any valuable metabolites are recovered by reabsorption. Flame cells are found in flatworms, including parasitic tapeworms and free-living planaria. They also maintain the organism's osmotic balance. Choices: - replication reaction - osmosis - metabolism - reabsorption A:
A: reabsorption

Question: Q: Osmotic pressure is important in biological systems because cell walls are what? Read this paragraph and choose the correct option from the provided answers: Osmotic pressure is important in biological systems because cell walls are semipermeable membranes. In particular, when a person is receiving intravenous (IV) fluids, the osmotic pressure of the fluid needs to be approximately the same as blood serum; otherwise bad things can happen. Figure 11.4 "Osmotic Pressure and Red Blood Cells" shows three red blood cells: Figure 11.4 "Osmotic Pressure and Red Blood Cells"a shows a healthy red blood cell. Figure 11.4 "Osmotic Pressure and Red Blood Cells"b shows a red blood cell that has been exposed to a lower concentration than normal blood serum (a socalled hypotonic solution); the cell has plumped up as solvent moves into the cell to dilute the solutes inside. Figure 11.4 "Osmotic Pressure and Red Blood Cells"c shows a red blood cell exposed to a higher concentration than normal blood serum (hypertonic); water leaves the red blood cell, so it collapses onto itself. Only when the solutions inside and outside the cell are the same (isotonic) will the red blood cell be able to do its job. Choices: - impassable - theonym membranes - variably membranes - semipermeable membranes A:
Answer: semipermeable membranes

*Question*
Q: What part of the cell is surrounded by a membrane and holds the genetic information for the cell? Read this paragraph and choose the correct option from the provided answers: All living cells are surrounded by a cell membrane. Plant cells (Figure 17.3 "An Idealized Plant Cell") and animal cells (Figure 17.4 "An Idealized Animal Cell") contain a cell nucleus that is also surrounded by a membrane and holds the genetic information for the cell. (For more information about genetics and DNA, see Chapter 19 "Nucleic Acids". ) Everything between the cell membrane and the nuclear membraneincluding Saylor URL: http://www. saylor. org/books. Choices: - cell wall - upper - lower - nucleus A:
**Answer**
nucleus

Q: Q: Magnetite crystals in lava typically point to what geographic location? Read this paragraph and choose the correct option from the provided answers: Magnetite crystals in the lava point in the direction of the magnetic north pole. The different stripes of magnetic polarity reveal the different ages of the seafloor. Choices: - the equator - magnetic south pole - geographic north pole - magnetic north pole A:
A: magnetic north pole