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thuyhang
2 năm trước
1 tế bào trải qua 1 số lần nguyên phân đã hình thành 2048 tế bào a, tìm số thế hệ tb nói trên b, sẽ hình thành bao nhiêu giao tử nếu chúng là tb sinh tinh , sinh trứng c, sẽ có bao nhiêu cá thể được hình thành nếu tất cả tế bào trứng đều được thụ tinh hết ?trong thực tế ko như vậy giải thích tại sao
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Bài 1: The Sloth What is a sloth? Did you know that a sloth is a slow-moving animal that lives in trees? Sometimes people are called sloths, but that’s not because they live in trees; rather, it’s because they are moving so slowly. A sloth spends most of its time hanging upside down in a tree. A sloth will eat, sleep, and give birth hanging upside down! Their curved claws make it easy for them to hang onto the tree. Sloths are four-legged animals. They spend almost all of their lives up in a tree. They walk upside down along the branches. Sloths are also known to be good swimmers. Sloths are found in Central and South America. The sloth is nocturnal, which means it is active at night instead of the day. This means that it sleeps during the day. The sloth usually keeps to itself, although some female sloths congregate in small groups. The sloth has a thick, brown coat of fur. They are plant-eaters and eat mostly leaves, tender shoots, and fruit. The sloth has green algae growing on its fur. The sloth will lick the algae for nutrients. The algae also helps protect the sloth from enemies. Eagles, jaguars, and humans hunt the sloth. The algae growing on the sloth helps to camouflage it. Story Questions 1. Inorderforaslothtoliveinatree,itneeds... a. courage. c. curved claws. b. to be the right size. d. to eat only plants. 2. According to the passage, how do sloths keep from being eaten? a. They are easily hidden. c. They are slow moving. b. They are camouflaged by green algae. d. They have thick, brown fur. 3. Why did the author include the first paragraph? a. to introduce the main points about the sloth b. to clear up misconceptions about the sloth c. to generate questions about the sloth d. to identify the food eaten by the sloth 4. The best way to find the answer to question #3 above is to . . . a. reread the entire passage. b. reread the first paragraph and determine the main idea. c. look for the words “sloth” and “habitat.” d. skim the passage and look for clues. Bài 2: The Rattlesnake Have you ever heard the rattle of a rattlesnake? In the wild, it can be one of the scariest sounds around. The rattlesnake is venomous, which means it is poisonous. A rattlesnake has something that sounds like a rattle at the end of its body. The rattle is an organ made up of loosely-attached pieces of horn. When rattled, the pieces of horn bounce against each other, making the rattle sound. The body of a rattlesnake is grayish or brownish gray with darker circular blotches along its back and sides. The underside of the rattlesnake is a creamish color. The rattle on a rattlesnake is used to warn an intruder that the snake is there. A rattlesnake usually bites a person when someone tries to catch, kill, or harm it. When a rattlesnake bites a person, he or she should be treated with anti-venom, which fights the poison in the body. Most people do not die when a rattlesnake has bitten them. But when people are bitten by a rattlesnake, they should receive immediate medical attention. What does a rattlesnake eat? A rattlesnake doesn’t want to eat a human when and if it bites one; it is only trying to defend itself. Rattlesnakes eat rodents. This helps control the rodent population. Rattlesnakes need rodents and a place to hide in order to survive. Rattlesnakes stay in the same general area, but they will not fight other rattlesnakes. Story Questions 1. How does the author feel about rattlesnakes? a. The author is in favor of rattlesnake control. b. The author has been bitten by a rattlesnake and dislikes them. c. The author is afraid of rattlesnakes. d. The author sees the need and purpose for rattlesnakes. 2. The second paragraph instructs readers on what . . . a. to do if they see a rattlesnake. b. to do if bitten by a rattlesnake. 3. Will a rattlesnake eat a human? a. Yes, if they are threatened by one. b. No, unless they are starving. c. a rattlesnake looks like. d. a rattlesnakes preys on. c. No, they eat rodents. d. Yes, when there are no rodents around. 4. Where might this information about the rattlesnake most likely be found? a. in a pamphlet on rattlesnakes b. on a cereal box c. in a book about rodents d. in a book about the Northwest

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