1.
What do scientists call a possible explanation for observations they have made?
Correct Answer
D. A hypothesis
Explanation
Scientists call a possible explanation for observations they have made a hypothesis. A hypothesis is a proposed explanation or prediction based on limited evidence or observations. It is a testable statement that can be further investigated through experiments or observations to determine its validity. Scientists use hypotheses to guide their research and to develop theories about how the natural world works.
2.
A student measured how much salt could be dissolved in water at five different temperatures. The student used 100mL of water and the same brand of salt for each trial. The manipulated variable was the ...
Correct Answer
A. Temperature of water
Explanation
The manipulated variable in this experiment was the temperature of water. This means that the student intentionally changed the temperature of the water in each trial to see how it affected the amount of salt that could be dissolved. The other variables, such as the mass of salt dissolved, brand of salt, and volume of water, were kept constant throughout the experiment. By changing only the temperature of the water, the student was able to determine its effect on the solubility of salt.
3.
Which of the following would you use to make the best model of a gas molecule?
Correct Answer
C. Toothpicks and foam balls
Explanation
To make the best model of a gas molecule, toothpicks and foam balls would be the most suitable materials. Toothpicks can be used to represent the bonds between atoms in the molecule, while foam balls can be used to represent the atoms themselves. This allows for a three-dimensional representation of the molecule, showing the arrangement of atoms and their connections. The other options, such as a globe or topographic map, are not suitable for modeling gas molecules as they do not provide the necessary components to represent the individual atoms and their bonds. Cardboard boxes and tape are also not appropriate materials for this purpose.
4.
How is digitizing used?
Correct Answer
B. To make maps
Explanation
Digitizing is the process of converting analog information into digital format. In the context of making maps, digitizing refers to the process of converting physical maps or other spatial data into a digital format. This allows for easier storage, manipulation, and analysis of the data. By digitizing maps, they can be easily accessed, updated, and shared, making them more efficient and accurate for various purposes such as navigation, urban planning, and resource management.
5.
Which characteristic of fiberglass would make a particularly good material for making outdoor furniture?
Correct Answer
D. It resists corrosion
Explanation
Fiberglass is a material that is known for its resistance to corrosion. This means that it can withstand exposure to outdoor elements such as moisture, sunlight, and temperature changes without deteriorating or rusting. This characteristic makes fiberglass a particularly good material for making outdoor furniture, as it can maintain its structural integrity and appearance over time, even when exposed to harsh weather conditions. Additionally, fiberglass is also lightweight, which makes it easy to move and transport, further adding to its suitability for outdoor furniture.
6.
Where is most of Earth's water located?
Correct Answer
C. In oceans
Explanation
Most of Earth's water is located in the oceans. The oceans cover about 71% of the Earth's surface and contain about 97% of the planet's water. They play a crucial role in regulating the Earth's climate, storing heat, and absorbing carbon dioxide. The remaining water is found in other sources such as lakes, rivers, underground aquifers, and the atmosphere. However, the vast majority of Earth's water is concentrated in the oceans.
7.
In which of the following forms is the metal manganese found on the ocean floor?
Correct Answer
B. Nodules
Explanation
Manganese nodules are small, rounded lumps of manganese and other metallic elements that are found scattered on the ocean floor. These nodules form over millions of years through chemical reactions in the sediment, and they contain high concentrations of manganese, as well as other valuable metals like copper, nickel, and cobalt. Therefore, the correct answer is nodules.
8.
Which of the following is an example of a non-point source of pollution?
Correct Answer
A. Runoff from a farm field
Explanation
Runoff from a farm field is an example of a non-point source of pollution because it is not originating from a single identifiable source, such as a specific pipe or tank. Instead, it is the result of water flowing over the land and picking up pollutants, such as fertilizers and pesticides, from various areas of the field. This runoff can then enter nearby water bodies, causing pollution on a larger scale.
9.
A material that is malleable
Correct Answer
C. Can be pounded into shape
Explanation
A material that can be pounded into shape is malleable. Malleability refers to the ability of a material to be easily deformed or shaped by applying pressure or force, typically through hammering or pounding. This property allows the material to be easily molded or reshaped without breaking or cracking. Therefore, a material that can be pounded into shape is considered malleable.
10.
If you know the length, width, and height of an object, you can determine the object's?
Correct Answer
D. Volume
Explanation
If you know the length, width, and height of an object, you can determine the object's volume. Volume is the measure of the amount of space occupied by an object. By multiplying the length, width, and height of an object, you can calculate its volume.
11.
Which of the following substances is a carcinogen?
Correct Answer
A. Tar in cigarette smoke
Explanation
Tar in cigarette smoke is a carcinogen because it contains numerous toxic chemicals, including polycyclic aromatic hydrocarbons (PAHs) and benzene. These substances have been proven to cause DNA damage and mutations, leading to the development of cancer. When inhaled, the tar particles can accumulate in the lungs and other organs, increasing the risk of lung, throat, and various other types of cancer. Additionally, the combustion of tobacco releases other harmful substances that further contribute to the carcinogenic effects of tar in cigarette smoke.
12.
Which of the following would scientists examine to learn about the global evolution of extinct organisms?
Correct Answer
B. The fossil record
Explanation
Scientists would examine the fossil record to learn about the global evolution of extinct organisms. Fossils are the preserved remains or traces of ancient organisms, providing valuable information about their morphology, behavior, and evolutionary history. By studying fossils found in different locations around the world, scientists can reconstruct the past biodiversity and understand how organisms have changed over time. Fossils also help in identifying the relationships between extinct species and their modern-day counterparts, providing insights into the evolutionary processes that have shaped life on Earth.
13.
How are cells produced?
Correct Answer
D. From other cells
Explanation
Cells are produced from other cells through the process of cell division. This is known as the cell theory, which states that all cells arise from pre-existing cells. During cell division, a parent cell divides into two or more daughter cells, each containing a complete set of genetic material. This process allows for growth, repair, and the production of new organisms. Therefore, the correct answer is "from other cells."
14.
Which of the following revolutionized map making in the twentieth century?
Correct Answer
C. Satellite images
Explanation
Satellite images revolutionized map making in the twentieth century. They provided a new and accurate way of capturing and visualizing the Earth's surface from above. These images allowed for detailed and up-to-date mapping of various features such as landforms, vegetation, and urban areas. Satellite images also enabled the creation of digital maps, which could be easily accessed and analyzed for various purposes such as urban planning, disaster management, and navigation. The use of satellite images in map making brought significant advancements and improvements in accuracy, efficiency, and accessibility compared to traditional methods.
15.
Which of the following is an antibiotic?
Correct Answer
B. Penicillin
Explanation
Penicillin is an antibiotic because it is a type of medication that fights bacterial infections. It works by inhibiting the growth of bacteria or killing them, helping the body's immune system to eliminate the infection. Insulin is a hormone used to regulate blood sugar levels in diabetes, tetanus is a bacterial infection caused by the Clostridium tetani bacteria, and diabetes is a medical condition characterized by high blood sugar levels.
16.
What do all protists have in common?
Correct Answer
C. They are all eukaryotes
Explanation
All protists have in common that they are eukaryotes. Eukaryotes are organisms that have cells with a nucleus and membrane-bound organelles. This distinguishes them from prokaryotes, which are organisms that lack a nucleus and membrane-bound organelles. Protists can be either unicellular or multicellular, and they can be autotrophs or heterotrophs. However, the one characteristic that all protists share is being eukaryotic.
17.
The stage during which a cell's nucleus divides into two nuclei is called?
Correct Answer
C. Mitosis
Explanation
During mitosis, a cell's nucleus divides into two nuclei. This process is crucial for the growth, development, and repair of organisms. It ensures that each new cell receives a complete set of chromosomes, allowing for genetic continuity. Osmosis is the movement of water across a semi-permeable membrane, unrelated to cell division. Cytokinesis is the final stage of cell division, where the cytoplasm divides into two daughter cells. Interphase is the stage where the cell prepares for division, but the nucleus does not divide.
18.
How do viruses compare to bacteria?
Correct Answer
D. Viruses are much smaller
Explanation
Viruses are much smaller than bacteria. While bacteria are single-celled organisms that can be seen under a microscope, viruses are much smaller and can only be observed using an electron microscope. Bacteria are independent living organisms, while viruses are considered to be non-living because they cannot replicate or carry out metabolic processes on their own.