Jane performed an experiment to learn more about plants. She purchased two pots and placed a rose plant sapling in each one. She made sure each pot contained the same amount of soil and fertilizer, then moved one pot next to a window and the other pot to a dark room. Every other day, she poured the same amount of water in each pot.
After two months, she found that the plant by the window had produced flowers, while the plant in the dark room was much smaller and had not flowered. Which of these was the independent variable in Jane's experiment?
A.
water
B.
sunlight
C.
soil
D.
fertilizer
B. sunlight
The independent variable in Jane's experiment was the amount of sunlight each plant received, as this was the variable that Jane manipulated and controlled.
Because they do not have wings, certain species of walking stick insects typically spend their entire lives on one bush. Some of these insects are solid green, while others have white stripes running up their bodies, as pictured below.
Image by Moritz Muschick (University of Sheffield), 2013.
Reproduced under the terms of the Creative Commons License, Attribution 2.0 Generic
Recently, scientists have noticed trends in the insects’ color patterns. Depending on the bush they inspect, the scientists may find mostly green bugs or mostly striped ones. How does this genetic variation in color increase the probability of survival for this species of insect?
A.
The insects’ coloring matches the coloring of the bush they live in to help them hide from predators.
B.
The insects’ coloring changes throughout their lifetimes to signify which are able to reproduce.
C.
The insects’ coloring helps them to distinguish the males from the females.
D.
The insects’ coloring lets predators know which of them are poisonous and which are not.
A. The insects’ coloring matches the coloring of the bush they live in to help them hide from predators.
The genetic variation in color allows the insects to blend in with their environment, increasing their chances of survival by avoiding predators.
The picture below shows a honeysuckle plant.
Honeysuckles produce a sweet, sugar-rich liquid called nectar, which is present inside each flower of the plant. Which of the following best describes the function of nectar?
A.
It helps plants perform photosynthesis more efficiently.
B.
It helps plants perform cellular respiration more efficiently.
C.
It attracts pollinators such as hummingbirds and insects.
D.
It provides seeds with nutrients as they grow.
C. It attracts pollinators such as hummingbirds and insects.
Nectar is produced by plants to attract pollinators such as hummingbirds and insects. These pollinators help in the process of pollination, which is essential for the plant's reproduction.
The diagram below shows an example of how an analog wave and a digital wave might be transferred.
This diagram provides evidence for which of the following statements?
A.
Digital waves are more reliable for transferring information than analog waves.
B.
Digital waves experience noise as they travel, whereas analog waves do not experience noise.
C.
Analog waves experience noise as they travel, whereas digital waves do not experience noise.
D.
Analog waves are more reliable for transferring information than digital waves.
C. Analog waves experience noise as they travel, whereas digital waves do not experience noise.
The diagram suggests that analog waves are more susceptible to noise interference during transfer compared to digital waves.
Sally turns on her cellular telephone to speak to her friend who is located thousands of miles away. Which of the following best describes how such a telephone is able to transmit and receive information?
A.
The cellular telephone transmits, receives, and encodes information using only electromagnetic waves.
B.
The cellular telephone transmits information by electromagnetic waves to a receiver which then encodes them and produces sound.
C.
The cellular telephone transmits information by sound waves to a receiver which then encodes them and produces electromagnetic waves.
D.
The cellular telephone transmits, receives, and encodes information using only sound waves.
A. The cellular telephone transmits, receives, and encodes information using only electromagnetic waves.
Cellular telephones transmit information wirelessly using electromagnetic waves to communicate with cell towers and other devices.