Ques: Q: What is the greek word meaning "to help make things easier"? Read this paragraph and choose the correct option from the provided answers: 9.5 Simple Machines Simple machines are devices that can be used to multiply or augment a force that we apply often at the expense of a distance through which we apply the force. The word for "machine" comes from the Greek word meaning "to help make things easier. " Levers, gears, pulleys, wedges, and screws are some examples of machines. Energy is still conserved for these devices because a machine cannot do more work than the energy put into it. However, machines can reduce the input force that is needed to perform the job. The ratio of output to input force magnitudes for any simple machine is called its mechanical advantage (MA). Choices: - toy - battery - mode - machine A:
Ans: machine

Ques: Q: All lipids have two distinct domains, a hydrophobic and a what? Read this paragraph and choose the correct option from the provided answers: Membrane boundaries and capturing energy In which we consider how the aqueous nature of biological systems drives the formation of lipidbased barrier membranes and how such membranes are used to capture and store energy from the environment and chemical reactions. We consider how coupled reactions are used to drive macromolecular synthesis and growth. Defining the cell's boundary A necessary step in the origin of life was the generation of a discrete barrier, a boundary layer, that serves to separate the living non-equilibrium reaction system from the rest of the universe. This boundary layer, the structural ancestor of the plasma membrane of modern cells, serves to maintain the integrity of the living system and mediates the movement of materials and energy into and out of the cell. Based on our current observations, the plasma membrane of all modern cells appears to be a homologous structure derived from a precursor present in the last common ancestor of life. So what is the structure of this barrier (plasma) membrane? How is it built and how does it work? When a new cell is formed its plasma membrane is derived from the plasma membrane of the progenitor cell. As the cell grows, new molecules must be added into the membrane to enable it to increase its surface area. Biological membranes are composed of two general classes of molecules, proteins (which we will discuss in much greater detail in the next section of the course) and lipids. It is worth noting explicitly here that, unlike a number of other types of molecules we will be considering, such as proteins, nucleic acids, and carbohydrates, lipids are not a structurally coherent group, that is they do not have one particular basic structure. Structurally diverse molecules, such as cholesterol and phospholipids, are both considered lipids. While there is a relatively small set of common lipid types, there are many different lipids found in biological systems and the characterization of their structure and function(s) has led to a new area of... Choices: - hydroceptive - covalent - hydroaversive - hydrophilic A:
Ans: hydrophilic

Ques: Q: What type of change has occurred when a copper penny changes color? Read this paragraph and choose the correct option from the provided answers: Some of these pennies are shiny and copper colored. That's how pennies look when they are new. The older pennies are dull and brown. Copper at the surface of these pennies has combined with air to become a different substance with different properties. The change in color shows that a chemical change has occurred. Choices: - contamination change - carbon change - reactive change - chemical change A:
Ans: chemical change

Ques: Q: What part of the plant is the main site of photosynthesis? Read this paragraph and choose the correct option from the provided answers: 30.4 Leaves Leaves are the main site of photosynthesis. A typical leaf consists of a lamina (the broad part of the leaf, also called the blade) and a petiole (the stalk that attaches the leaf to a stem). The arrangement of leaves on a stem, known as phyllotaxy, enables maximum exposure to sunlight. Each plant species has a characteristic leaf arrangement and form. The pattern of leaf arrangement may be alternate, opposite, or spiral, while leaf form may be simple or compound. Leaf tissue consists of the epidermis, which forms the outermost cell layer, and mesophyll and vascular tissue, which make up the inner portion of the leaf. In some plant species, leaf form is modified to form structures such as tendrils, spines, bud scales, and needles. Choices: - soil - root - stem - leaf A:
Ans:
leaf