Orchids are unique in having the most highly developed of all blossoms, in which the usual male and female reproductive organs are fused in a single structure called the column. The column is designed so that a single pollination will fertilize hundreds of thousands, and in some cases millions, of seeds, so microscopic and light they are easily carried by the breeze. Surrounding the column are three sepals and three petals, sometimes easily recognizable as such, often distorted into gorgeous, weird, but always functional shapes. The most noticeable of the petals is called the labellum, or lip. It is often dramatically marked as an unmistakable landing strip to attract the specific insect the orchid has chosen as its pollinator. To lure their pollinators from afar, orchids use appropriately intriguing shapes, colors, and scents. At least 50 different aromatic compounds have been analyzed in the orchid family, each blended to attract one, or at most a few, species of insects or birds. Some orchids even change their scents to interest different insects at different times.

   Once the right insect has been attracted, some orchids present all sorts of one-way obstacle courses to make sure it does not leave until pollen has been accurately placed or removed. By such ingenious adaptations to specific pollinators, orchids have avoided the hazards of rampant crossbreeding in the wild, assuring the survival of species as discrete identities. At the same time they have made themselves irresistible to collectors.

The orchid is unique because of ........

Câu hỏi liên quan

• After which year did the town really begin developing?

• In the first paragraph, the word “elements” is closest in meaning to____.

• It can be inferred from the passage that the Puritans who traveled to the Massachusetts colony were __________.

ZUNIA12

• An example of an amphibian’s incomplete adaptation to land life is…….

• The reason why telecommuting has not become popular is that the employees .............

• Which of the following is closest in meaning to the word “tuck” in line 11?

• According to the passage, the frame buffers mentioned in the third paragraph are used to ........

• The author mentions all of the following as concerns of telecommuting, EXCEPT ___________ .

• When the author says parents are “left in the dark”, he means that they ____________

• The word “They” in paragraph 2 refers to ...............

• The author mentions the “ shoesbox under the bed” in order to ................

• Did the town people believe the story of the five men about their meeting with Bigfoot?

• The underlined pronoun “they”refers to ...............

• The main idea of this passage is________.

• According to the passage, when will information stay in your short-term memory?

• The word “doubtless” in the passage mostly means ...............

• The expression “ keep tabs on” is closest meaning to ___________.

• Who opposed the bill that was introduced in the House of Commons in the early 1900s?

• According to the article, what does the band Four Square hope to do in the future?

• According to paragraph 1, the author of the passage argues that ................