1. Refraction and reflection of light] Seven-color light
2. Fluid flow rate
With high flow velocity and low pressure,
item A, the woodpecker’s beak is very pointed, which can reduce the force-bearing area and increase the pressure, so as to dig through the trunk and catch the insects hidden in the depths.
Item B, when the window is opened, the curtain floats outward, because the air flow rate outside the window is fast and the pressure is small, and the air flow rate inside the car is slow and the pressure is strong, so that the outward pressure difference is generated, correct;
In item C, the dam was built with upper narrow and lower width because the liquid pressure increased with the increase of depth, so the dam was built into a trapezoid with upper narrow and lower width, which increased the bearing capacity of water, which was wrong;
Item D, the kite is lifted into the air using the lift generated by the different air flow rates above and below the kite, not because of the buoyancy of the air, it is wrong.
Therefore, the correct answer is B.
3. Buoyancy
The two small balls A and B are in a balanced state under the action of gravity and buoyancy. From the balance condition, we get:,. The small ball C is in a balanced state under the action of gravity, buoyancy and supporting force. From the balance condition we get:, so. From the meaning of the question:, therefore, according to the buoyancy formula, it can be seen from the question stem graph:, then. From the meaning of the question, the depths of the three liquids are equal. According to the pressure formula:, it can be seen that the pressure of the liquid on the bottom of the container is,,, because, so, the B term is correct.
Therefore, the correct answer is B.
4.
Item A, spraying salt solution can reduce the freezing point of water, so as to achieve the purpose of melting (the freezing point is lowered, and the temperature is lower to freeze, so it is equivalent to melting ), so this method can be used, correct;
Item B, using a hard paper object to remove some ice directly, so this method can be used, correct;
Item C, start the car, turn on the hot air, and blow the front window glass of the car to melt the ice due to heat absorption and achieve the purpose of deicing, so this method can be adopted and correct;
Item D, sprinkling boiling water on the front window glass of the car, because the temperature of the water is very high, the ice and glass will quickly absorb heat and expand, which may cause the glass to break. Therefore, this method cannot be used and is wrong.
This question is an optional question, so the correct answer is D.
5.
6. Biology questions
Item A, carbon in the ecosystem circulates between the biological community and the inorganic environment. Producers, consumers, and decomposers all participate in the carbon cycle. Therefore, if an arrow is added, the arrow should point from the consumer to M, which is correct;
In item B, if M represents the atmosphere, then the carbon element circulates in the form of carbon dioxide between the inorganic environment and the biological community , then ①②③ both indicate that the transmission of carbon element in the biological community is mainly transmitted in the form of organic matter along the food chain , so ④ is Organic matter, error;
Item C, in green plant cells, the organelles involved in energy conversion include chloroplast and mitochondria. Chloroplast is the place for photosynthesis, which converts inorganic matter into organic matter and stores energy; mitochondria is the main place for cell respiration, which decomposes organic matter and releases energy. ,correct;
Item D, the energy in the surface ecosystem comes from the sun fixed by the producer, and the energy source of very few microorganisms in the depths is geothermal energy, correct.
This question is an optional question, so the correct answer is B.
7. Ridges, valleys
According to the contour line in the figure, it can be judged that the contour line at A protrudes toward the low altitude direction, which is a ridge; the contour line at B protrudes toward the high altitude direction, which is a valley; the ridge and valley can be judged by making a ridge line or a valley The vertical line of the line (the dashed line in the figure) judges the ridges or valleys based on the elevation of both sides and the elevation of the middle on the same horizontal plane. C and D are hillsides. The place suitable for rafting should be in the valley, because there are rivers in the valley, suitable for rafting.
Therefore, the correct answer is B.
8. Overweight and weightlessness
The upward acceleration is overweight, and the downward acceleration is weightlessness. The elevator is overweight when it just starts to accelerate up or decelerate, and it is weightless when it starts to accelerate or decelerate.
