Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions:
Archimedes’s Principle is a law of physics that states that when an object is totally or partially immersed in a fluid, it experiences an upthrust equal to the weight of the fluid displaced. The principle is most frequently applied to the behaviour of objects in water, and helps to explain floating and sinking, and why objects seem lighter in water. It also applies to balloons.
The key word in the principle is “upthrust”, which refers to the force acting upward to reduce the apparent weight of the object when it is under water. If, for example, a metal block with a volume of 100 cm3 is dipped in water, it displaces an equal volume of water, which has a weight of approximately 1 N (3.5 oz). The block therefore seems to weigh about 1 N less.
An object will float if its average density is less than that of water. If it is totally submerged, the weight of the water it displaces (and hence the upthrust on it) is greater than its own weight, and it is forced upward and out of water, until the weight if water displaced by submerged part is exactly equal to the weight of the floating object. Thus a block of wood with a density six tenths that of water will float with six tenths of its volume under water, since at that point the weight of fluid displaced is the same as the blocks’s own weight. If a dense material is made into a suitable shape, it will float because of Archimedes’s principle. A ship floats, whereas a block of iron of the same mass sinks.
It is also because of Archimedes’s principle that ships float lower in the water when they are heavily loaded (more water must be displaced to give the necessary upthrust). In addition, they cannot be so heavily loaded if they are to sail in fresh water as they can if they are to sail in the sea, since fresh water is less dense than sea water, and so more water must be displaced to give the necessary upthrust. This means the ship is lower in the water, which can be dangerous in rough weather.
A block of wood with a density seven tenths that of water will .
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Lời giải:
Báo saiGiải thích: The dulotic species of ants, however, are the supreme social parasites … To compensate for these deficits, Polyergus has become specialized at obtaining workers from the related genus Formica to do these chores.
Dịch nghĩa: Các loài kiến, tuy nhiên, là những ký sinh trùng xã hội tối cao ... Để bù đắp cho những thiếu hụt, Polyergus đã trở nên chuyên về lấy những công nhân từ chi liên quan Formica để làm những công việc nhà.
Như vậy có thể suy ra rằng tác giả nói kiến là loài kí sinh tối cao vì loài Polyergus phụ thuộc năng nề vào loài Formica.
Phương án C. The Polyergus are heavily dependent on the Formica = Polyergus phụ thuộc rất nhiều vào Formica; là phương án chính xác nhất.
The Polyergus are more highly developed than the Formica = Chi Polyergus đang phát triển cao hơn chi Formica.
The Formica have developed specialized roles = Chi Formica đã phát triển những vai trò đặc biệt.
D. The Formica do not reproduce rapidly enough to care for themselves = Chi Formica không sinh sản nhanh chóng đủ để chăm sóc bản thân.