Question 1

Researchers set up a study to determine whether large doses of a nutritional supplement would shorten the length of time it takes to recover from a cold. Three thousand volunteers were split into two groups. For two weeks, members of group A took 3,000 mg of the supplement daily. Group B received 3,000 mg of a placebo (sugar pill). At the end of the two-week period, the researchers inserted live cold viruses directly into the noses of all the volunteers. The volunteers in both group A and group B continued to take their daily pills. All the volunteers got colds, and there was no significant difference in the length of time the colds lasted.
-To have confidence that the results of the experiment were valid, you'd also want to know

Accepted Answer

Knowing whether any volunteers had colds at the start of the experiment would help to control for this variable and avoid confounding the results. C and B are not relevant to knowing whether the results of the experiment were valid.

Question 2

Which statement is not an example of evolution that has resulted from human activity?

Accepted Answer

This statement is not an example of evolution resulting from human activity because it describes the reduction in population size due to hunting rather than genetic changes in response to human influence. A, B, and D are all examples of evolution resulting from human activity because they describe genetic changes in response to antibiotic use, selective breeding, and pesticide use, respectively.

Question 3

Which statement provides the best evidence that there is a common genetic code that demonstrates the unity of life?

Accepted Answer

The fact that a gene from a firefly can be inserted into a bacterium to make it glow demonstrates that there is a common genetic code used by all living organisms, regardless of their evolutionary history. The genetic code is a universal language that allows for the transfer of genetic information across different species. This supports the idea of the unity of life, as all living organisms share a common ancestry and use the same genetic code to carry out their essential functions.

Question 4

The role of a control in an experiment is to

Accepted Answer

A control group is used to provide a baseline for comparison with the experimental group, allowing researchers to determine whether the changes seen in the experimental group are due to the treatment or some other factor. This is important for ensuring validity and reliability in experimental results. B is incorrect because the role of a control group is not to prove a hypothesis, but rather to test it. C is partly accurate, but repeatability is achieved through replication of the experiment, not just by the presence of a control group.

Question 5

Researchers have created a robot that has a very thin leg that is moved by cardiac (heart) cells contracting in unison. The robot, made of a polymer similar to that used in making contact lenses, is bathed in heart cells with supporting cells, which then attach to the robot and provide movement as they contract.
-If the creators of the robot wanted to provide evidence that it is alive, which of the following properties would be best to use as evidence?

Accepted Answer

The requirement for a liquid medium to provide nutrition for its cells suggests a biological process of metabolism, which is a characteristic of living organisms. Movement alone (A) does not imply life, as many non-living systems can move. Reproduction by researchers (C) is not a biological process of the robot itself. Having different types of cells (D) indicates complexity but does not directly evidence life without showing biological processes like metabolism, growth, or self-replication.

Question 6

During a discussion about ecosystems, a student says, "Plants eat sunlight, and animals eat other organisms." Which response to the student's comment is most accurate?

Accepted Answer

The student's statement is partially correct in that plants use sunlight to create energy through photosynthesis, but they do not actually "eat" or consume sunlight. Instead, they use this energy to create sugars that they need for survival. Therefore, choice B is the most accurate response.

Question 7

Researchers have created a robot that has a very thin leg that is moved by cardiac (heart) cells contracting in unison. The robot, made of a polymer similar to that used in making contact lenses, is bathed in heart cells with supporting cells, which then attach to the robot and provide movement as they contract.
-The robot's cardiac cells, working together in synchrony, could be considered at what level in life's hierarchy of organization?

Accepted Answer

The cardiac cells in the robot are working together to provide movement, but they are not functioning as a complete organism or organ system. They also do not make up an organelle within a cell. Therefore, the best choice is C) tissue.

Question 8

To be scientifically valid, a hypothesis must be

Accepted Answer

For a hypothesis to be scientifically valid, it must be testable and falsifiable which means it can be tested through experimentation and observation, and its premise can be proven false or rejected based on the results of such experimentation. While being part of a theory and being reasonable may also be desirable qualities, they are not a necessary condition for a hypothesis to be scientifically valid. Being controlled may be important for experimental design but it is not a requirement for a hypothesis itself to be valid.

Question 9

The box numbered 2 represents which process?

Accepted Answer

The box numbered 2 represents the cycling of matter, which refers to the movement of nutrients and other matter through biotic and abiotic components of an ecosystem. This can include processes such as nutrient uptake by plants, consumption of those plants by herbivores, and decomposition of dead plant and animal material by decomposers. Option A is incorrect because cycling of energy would involve the transfer of energy through the ecosystem, whereas option B is too broad as it implies that all parts of the system are being acted upon by decomposers, which may not always be the case. Option D is also incorrect as it refers to a specific phenomenon (atmospheric gases blocking sunlight), which is not related to the process represented by box 2.

Question 10

Which of the following organisms belongs to the group represented in box 1?

Accepted Answer

The answer of Which of the following organisms belongs to...

Question 11

Which statement about ecosystems is false?

Accepted Answer

Energy does not cycle through the atmosphere, but rather it flows through the ecosystem from producers to consumers and eventually to decomposers, where it is released as heat. The carbon cycle (B), conversion of sunlight to sugar (C), and most energy leaving as heat (D) are all accurate statements about ecosystems.

Question 12

When a scientist examined museum specimens of a particular moth species, she noticed that the variation in color was distributed as shown in the first graph. She was surprised because her data from current collections indicated the distribution of colors shown in the second graph. Which hypothesis about the cause of this shift in the range of genetic variation is the most likely to be supported by examination of the distribution of colors in a collection assembled at a time between that of the collection of the museum specimens and her current specimens?

Accepted Answer

The shift in the range of genetic variation from lighter to darker moths over time suggests that darker moths were more likely to survive and have offspring, while lighter moths were being selected against by predation. Therefore, the most likely hypothesis to be supported by the examination of the intermediate collection is that the shift towards darker moths was driven by natural selection.

Question 13

Watching salt crystals form as ocean water evaporates, a student says, "Look-more and more crystals are appearing. The ocean water is alive!" Which statement is an accurate evaluation of the student's remark?

Accepted Answer

Crystals forming from evaporating ocean water do not exhibit characteristics of living organisms, such as variation and adaptation.

Question 14

Researchers set up a study to determine whether large doses of a nutritional supplement would shorten the length of time it takes to recover from a cold. Three thousand volunteers were split into two groups. For two weeks, members of group A took 3,000 mg of the supplement daily. Group B received 3,000 mg of a placebo (sugar pill). At the end of the two-week period, the researchers inserted live cold viruses directly into the noses of all the volunteers. The volunteers in both group A and group B continued to take their daily pills. All the volunteers got colds, and there was no significant difference in the length of time the colds lasted.
-Which was the experimental group?

Accepted Answer

Group A was the experimental group because they received the nutritional supplement, while Group B received a placebo. The researchers were testing whether the supplement would shorten the length of time it takes to recover from a cold, so the group receiving the supplement was the experimental group.

Question 15

Which level in the hierarchy shown is a community?

Accepted Answer

The answer of Which level in the hierarchy shown is...

Question 16

Basic science discoveries often lead to the development of technology, and the development of technology often leads to new scientific discoveries. Which of the following is not an accurate pairing of a technology and a discovery?

Accepted Answer

The invention of the microscope directly led to the understanding of cell structure and microorganisms, but not necessarily to the creation of evolutionary trees. Evolutionary trees rely on genetic and molecular data, which were not accessible until after the development of modern molecular biology techniques.

Question 17

Researchers have created a robot that has a very thin leg that is moved by cardiac (heart) cells contracting in unison. The robot, made of a polymer similar to that used in making contact lenses, is bathed in heart cells with supporting cells, which then attach to the robot and provide movement as they contract.
-All of the cardiac cells working together can cause the robot leg to move in a way that individual cells could not. This is an example of

Accepted Answer

The movement of the robot leg created by the collective behavior of the heart cells is an example of emergent properties of cells, where the behavior of a system cannot be explained by analyzing the properties of individual components alone. Adaptation, energy flow through an ecosystem, and internal environment regulation are not applicable in this scenario.

Question 18

Which sequence is not a correct pathway of energy through an ecosystem?

Accepted Answer

Bacteria do not typically serve as a primary energy source for plants; plants obtain energy from sunlight through photosynthesis.

Question 19

A scientist performs a controlled experiment. This means that

Accepted Answer

A controlled experiment involves conducting two versions of the experiment, one with a variable manipulated (experimental group) and the other without the manipulated variable (control group). This allows the scientist to isolate the effects of the variable being tested. The other choices do not accurately describe a controlled experiment.

Question 20

Which model is best studied through a systems approach?

Accepted Answer

The biogeochemical cycling of nutrients involves the interactions between living organisms, the atmosphere, water, and the Earth's crust. It is a complex system that can best be studied through a systems approach. The other models listed can be studied through simpler and more reductionist approaches.

Quiz 1: Biology: Exploring Life