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because they know that winter is coming and they will need food. What they do
is automatic and fixed. The difference between the bees that make honey and the
bees called drones that do not work is not one in thought or laziness. The two
groups simply have different body structures and respond accordingly.
II. Study the notes, consult a dictionary about the way the words are
pronounced.
misleading зд. неверный
stimuli (pl.
ОТ stimulus) стимулы
bee пчела
honey мед
drone трутень
III. Find the topical sentence of the text, make up a model of the text
information and sum it up.
Text 23
I. Read the text and state what information it carries.
SYMBIOSIS
Associations are not confined to members of the same species, nor are all
an expression of cooperative adaptations. All graduations occur from those
which are mutually beneficial to the parties in the pact, to those in which one
member secures all the advantage at the expense of the other.
The most intimate associations in which the organisms involved are
mutually benefited, if not absolutely necessary for each other's existence, are
termed symbiotic. A familiar case is the common green Hydra (Chlorhydra
viridissima) that owes its colour to the presence of a large number of unicellular
green plants which live in its endoderm cells. The products of the photosynthetic
activity of the plant cells are at the disposal of the Hydra, and the latter, in return,
affords a favourable abode and the material necessary for the life of the plants.
A far more striking example of symbiosis is afforded by Lichens which
represent intimate combinations of various species of colourless plants (Fungi)
and simple green plants (Algae). In each case the Fungus supplies attachment,
protection, and the raw materials of food, while the Alga performs
photosynthesis. Each can live independently under favourable conditions, but in
partnership they are superior to hardships with which many other plants cannot
cope, and thus some Lichens become the vanguard of vegetation in repopulating
rocky, devastated areas.
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