Предмет: Биология, автор: Аноним

Что такое устьица? Какое строение они имеют? Каково значение устьиц для растений?

Ответы

Автор ответа: frogden

1) Устьица — это отверстия в эпидермисе, через которые происходит газообмен.
2) Устьице состоит из двух замыкающих клеток и устьичной щели между ними. К замыкающим примыкают побочные (околоустьичные) клетки. Под устьицем расположена воздушная полость. Устьица способны автоматически закрываться или открываться по мере необходимости. Это обусловлено тургорными явлениями.

3) Устьица выполняют две основные функции: осуществляют газообмен и транспирацию.

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Choose the option that best completes the sentence.

1. Arthur could not but ______ at her with admiration.
A. glance B. to glance C. glancing D. to be glancing

2. We’re having a wonderful holiday on the beach. I wish you ______ here.
A. are B. were C. had been D. be

3. Avoid ______ and you’ll feel better soon.
A. to overeat B. overeat C. overeating D. having overeating

4. If he _____ on me tomorrow, I will tell him everything.
A. called B. calls C. will call D. would call

5. Stop ______ my hair! It hurts!
A. pull B. pulling C. to pull D. to be pulling

6. He father strongly objected _______.
A. of smoking B. to smoking C. from smoking D. against smoking

7. ______ by the teacher regularly, the exercises are very useful to the students.
A. having been checked B. checking C. having checked D. being checked

8. If I had been told about the meeting a day earlier, I ______ it much better.
A. would arrange B. would have arranged C. will arrange D. arranged

9. They described the method ______ by this engineer.
A. using B. having used C. used D. have used

10. I want ______ more careful with your homework in the future.
A. you to be B. you be C. that you are D. your being

11. The girl couldn’t let herself ______.
A. crying B. cry C. to cry D. having cried

12. I would understand you better if I _______ of your age.
A. am B. were C. had been D. would be

13. He couldn’t get used ______ a grandfather, though he had two grandsons.
A. to call B. to be called C. to being called D. to calling

14. Would you mind ______ our cat while we’re away on holiday?
A. feed B. to feed C. feeding D. having fed

15. Garraway looked at Poirot with some surprise. He seemed ______ for more.
A. to be waiting B. to wait C. wait D. be waiting

16. I think we’d better ______ home rather than ______ here.
A. go, stay B. to go, to stay C. to go, stay D. go, to stay

17. You _______ better marks now, if you had worked harder during the year.
A. would have B. would have had C. will have D. had

18. This computer is useless. I wish my parents ______ a better one when they bought it.
A. had chosen B. chose C. have chosen D. choose

19. The students were made ______ their projects?
A. rewrite B. rewriting C. rewritten D. to rewrite

20. He hated all the people at the station once _______ one of them himself.
A. been B. being C. to have been D. having been

21. I remember ______ to the bank but nothing after that.
A. to go B. go C. going D. to have gone

22. ______ her by her arm, he helped her out of the carriage.
A. being supported B. supporting C. having been supported D. supported

23. ______ in the archaic language many centuries ago, the book was difficult to read.
A. having written B. writing C. having been written D. being written

24. I can’t say I enjoy ______ in the company of her relatives.
A. to be B. being C. be D. having been

25.He regrets ______ with the referee as it resulted in his _______ off the pitch.
A. arguing, sending B. to argue, sent C. having argued, to be sent D. arguing, being sent

Task 2. Use the verbs in brackets in the required form.

1. We were late. Tom suggested (take) a taxi.
2. He wore dark glasses as he avoided (recognize).
3. You are expected (know) the safety regulations of the college.
4. He made me (repeat) his instructions.
5. Before (give) evidence you must swear to speak the truth.
6. When I was a child, my hair used to (be) much blonder than now.
7. I regret (inform) you that your application has been refused.
8. When I arrived there I didn't see the dog. Not much else seemed (change).
9. (Hear) the sounds of music, we stopped talking.
10. A word (speak) in time may have very important results.
11. If someone (come) into the library, smile and say:”May I help you?”
12. Liza wishes she (be) brave enough to go scuba-diving.
13. If humans (vanish) from the Earth, endangered species would not necessarily recover.
14. Hurry up! We (not/get) good seats if we arrive late.
15. If the driver (slow down) at the right moment, he wouldn’t have had an accident.