ВУЗ:
Составители:
Рубрика:
Another animal that defends itself or its territory with a smell is a skunk. It
gives a warning signal by stamping its feet. Then it turns around, lifts its tail,
and sprays a terrible-smelling substance.
Some animals communicate by touching. Lions, tigers, and other members
of the cat family show friendliness by rubbing their heads or necks together.
Color is sometimes very important in animal communication. Some kinds
of fish change color when they are angry or frightened. A peacock displays the
beautifully colored feathers in hie tall when he «ante to attract a f mini».
The next time you are walking in a forest or a field, look and listen for
animal signals. But if you see scratches in a tree high above your head, find
another place to walk!
Notes:
hen курица
chick цыпленок
fall (амер.)осень
fawn молодой олень
chin подбородок
skunk скунс
peacock павлин
feather перо
Text 32
GRAMMES OF ANTIHORMONES INSTEAD
OF TONNES OF PESTICIDES
Some five or ten grammes of the substance developed at the laboratory
headed by Corresponding Member of the USSR Academy of Sciences Igor
Torgov are enough to rid one hectare of farmland of agricultural pests.
Toxic chemicals, or pesticides, widely applied today for pest control, kill
crop-eaters and help considerably increase yields and lower their costs*
However, at the same time, pesticides harmfully tell on the ecological balance.
Along with the pests, their enemies are devastated as well, and as a result,
the former restore their population and continue to multiply uncontrollably.
Bees and bumblebees avoid flowers which have changed their fragrance
under the influence of the pesticides. Thus plants stop being normally pollinated,
and this has a harmful effect on agriculture.
In a word, pesticides should be used only in extreme cases and only in locations
where the pest population surpasses certain limits and is hazardous to the crops.
Very simple traps Help determine these localities. Three or four traps are
placed in a one-hectare area and are checked weekly. Pests are attracted into the
66
Страницы
- « первая
- ‹ предыдущая
- …
- 65
- 66
- 67
- 68
- 69
- …
- следующая ›
- последняя »
