1. Which of the following is a biotic factor that might affect the life of a water-dwelling organism?
A. Temperature of the water
B. Speed of water current
C. Pollutions in water
D. Bacterial population in water
My guess: D?
2. Which of the following things does NOT allow plants to obtain atmospheric nitrogen in a more usable form?
A. Photosynthesis
B. Lightning
C. Symbiotic bacteria
D. Chemical fertilizers
My guess: A?
3. How does the amount of water on Earth change as a result of the water cycle?
A. It always increases
B. It alternately increases and decreases
C. It remains constant
D. It always decreases
My guess: C?
Thnak You ! =]
1. The correct answer is C. Pollutions in water. Biotic factors are living organisms or their products that can affect the life of other organisms. Pollution, such as chemicals or toxins in the water, is a biotic factor that can impact water-dwelling organisms.
2. The correct answer is D. Chemical fertilizers. Plants are unable to directly absorb atmospheric nitrogen as a usable form. However, certain bacteria, known as nitrogen-fixing bacteria, can convert atmospheric nitrogen into a form that plants can use. Lightning also plays a role in converting atmospheric nitrogen into a usable form through a process called lightning fixation. Chemical fertilizers provide nitrogen to plants in a more accessible form, but they do not cause plants to obtain atmospheric nitrogen directly.
3. The correct answer is B. It alternately increases and decreases. The water cycle is a continuous process of evaporation, condensation, and precipitation that circulates water on Earth. While water is evaporated from the surface, it rises into the atmosphere, forms clouds, and eventually returns to the surface as precipitation. Therefore, the amount of water on Earth changes in a cyclical pattern, with water continually being redistributed and recycled.
1. Great job! You are correct. The biotic factor that might affect the life of a water-dwelling organism is the bacterial population in water (Choice D). Biotic factors are living or once-living components of an ecosystem, and bacteria play an essential role in the health and balance of aquatic environments.
To arrive at your answer, you needed to understand what biotic factors are and then think about which option fits that definition. By process of elimination, you correctly identified the option that represents a living component (bacterial population) over the abiotic factors such as water temperature, water current speed, and pollution.
2. Well done! Your answer is correct. Photosynthesis (Choice A) is not a process that directly enables plants to obtain atmospheric nitrogen in a more usable form. Instead, plants primarily utilize nitrogen in the form of nitrates or ammonia, which they acquire through other means.
To determine your answer, you had to understand the various ways that plants can acquire nitrogen. Choices B, C, and D, all involve processes or agents that facilitate the conversion of atmospheric nitrogen into usable forms for plants. In contrast, photosynthesis is not directly involved in this process. Therefore, Choice A is the correct answer.
3. Nice job! You are correct again. The amount of water on Earth remains relatively constant (Choice C) as a result of the water cycle. The water cycle is the continuous movement and exchange of water between the Earth's surface, atmosphere, and back. Although water changes form during the cycle, the overall amount of water on Earth does not change significantly.
To answer this question correctly, you needed to have a basic understanding of the water cycle and how it works. By ruling out options A, B, and D, which suggest that the amount of water either continually increases, decreases, or alternates between the two, you correctly identified that the total amount of water on Earth remains relatively constant.
Great job on all three questions! If you have any more questions, feel free to ask.
The portion of Earth that supports existence of living things is called the-
C. Biosphere!