Why do animals form swarms? - Maria R. D'Orsogna

321,735 views ใƒป 2017-12-18

TED-Ed


ืื ื ืœื—ืฅ ืคืขืžื™ื™ื ืขืœ ื”ื›ืชื•ื‘ื™ื•ืช ื‘ืื ื’ืœื™ืช ืœืžื˜ื” ื›ื“ื™ ืœื”ืคืขื™ืœ ืืช ื”ืกืจื˜ื•ืŸ.

ืชืจื’ื•ื: Ido Dekkers ืขืจื™ื›ื”: Sigal Tifferet
00:08
When desert locusts are well fed, they're solitary creatures.
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ื›ืฉืืจื‘ื” ืžื“ื‘ืจื™ ืื•ื›ืœื™ื ื”ื™ื˜ื‘, ื”ื ื™ืฆื•ืจื™ื ืžืชื‘ื•ื“ื“ื™ื.
00:11
But when food becomes scarce,
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ืื‘ืœ ื›ืฉื”ืื•ื›ืœ ื”ื•ืคืš ืœื ื“ื™ืจ,
00:13
hungry, desperate locusts crowd onto small patches of land
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ื”ืืจื‘ื” ืจืขื‘ื™ื ื•ืžื™ื•ืืฉื™ื ื•ืžืฆื˜ื•ืคืคื™ื ื‘ืฉื˜ื—ื™ื ืงื˜ื ื™ื
00:17
where they can still find something to eat.
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ืฉื ื”ื ืขื“ื™ื™ืŸ ื™ื›ื•ืœื™ื ืœืžืฆื•ื ืžืฉื”ื• ืœืื›ื•ืœ.
00:19
Contact between different locusts' hind legs set off a slew of reactions
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ืžืคื’ืฉ ื‘ื™ืŸ ืจื’ืœื™ื™ื ืื—ื•ืจื™ื•ืช ืฉืœ ื›ืžื” ืืจื‘ื” ืžืคืขื™ืœ ืฉืจืฉืจืช ืชื’ื•ื‘ื•ืช
00:24
that change their appearance and behavior.
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ืฉืžืฉื ื•ืช ืืช ื”ืžืจืื” ื•ื”ื”ืชื ื”ื’ื•ืช ืฉืœื”ื.
00:27
Now, instead of shunning their peers, they seek each other out.
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ืขื›ืฉื™ื•, ื‘ืžืงื•ื ืœื“ื—ื•ืช ืืช ืขืžื™ืชื™ื”ื, ื”ื ืžื—ืคืฉื™ื ืื—ื“ ืืช ื”ืฉื ื™.
00:31
The locusts eventually start marching and then fly away in large numbers
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ื”ืืจื‘ื” ืœื‘ืกื•ืฃ ืžืชื—ื™ืœ ืœืฆืขื•ื“ ื•ืื– ืœืขื•ืฃ ื‘ืžืกืคืจื™ื ื’ื“ื•ืœื™ื
00:35
seeking a better habitat.
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ืžื—ืคืฉื™ื ืžืงื•ื ืžื—ื™ื” ื˜ื•ื‘ ื™ื•ืชืจ.
00:37
These gigantic swarms can host millions of insects
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ื”ื ื—ื™ืœื™ื ื”ืขืฆื•ืžื™ื ื”ืืœื” ื™ื›ื•ืœื™ื ืœืืจื— ืžืœื™ื•ื ื™ ื—ืจืงื™ื
00:40
and travel thousands of miles,
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ื•ืœื ื•ืข ืืœืคื™ ืงื™ืœื•ืžื˜ืจื™ื,
00:42
devastating vegetation and crops.
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ืœื”ืฉืžื™ื“ ืฆืžื—ื™ื” ื•ื™ื‘ื•ืœื™ื.
00:45
They stay close to each other, but not too close,
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ื”ื ื ืฉืืจื™ื ืงืจื•ื‘ ืื—ื“ ืœืฉื ื™, ืื‘ืœ ืœื ืงืจื•ื‘ ืžื“ื™,
00:48
or they might get eaten by their hungry neighbors.
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ืื• ืฉื”ื ื ืื›ืœื™ื ืขืœ ื™ื“ื™ ืฉื›ื ื™ื”ื ื”ืจืขื‘ื™ื.
00:52
When many individual organisms, like locusts,
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ื›ืฉื”ืจื‘ื” ืคืจื™ื˜ื™ื ืฉืœ ืื•ืจื’ื ื™ื–ื ื›ืžื• ืืจื‘ื”,
00:55
bacteria,
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ื‘ืงื˜ืจื™ื•ืช,
00:56
anchovies,
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ืื ืฉื•ื‘ื™,
00:57
or bats,
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ืื• ืขื˜ืœืคื™ื,
00:58
come together and move as one coordinated entity,
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ืžืชืื—ื“ื™ื ื•ื ืขื™ื ื›ื™ืฉื•ืช ืžืชื•ืืžืช ืื—ืช,
01:01
that's a swarm.
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ื–ื” ื ื—ื™ืœ.
01:03
From a handful of birds to billions of insects,
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ืžืžืกืคืจ ืฆื™ืคื•ืจื™ื ืœืžื™ืœื™ืืจื“ื™ ื—ืจืงื™ื,
01:06
swarms can be almost any size.
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ื ื—ื™ืœื™ื ื™ื›ื•ืœื™ื ืœื”ื™ื•ืช ื›ืžืขื˜ ื‘ื›ืœ ื’ื•ื“ืœ.
01:09
But what they have in common is that there's no leader.
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ืื‘ืœ ืžื” ืฉืžืฉื•ืชืฃ ืœื”ื ื–ื” ืฉืื™ืŸ ืžื ื”ื™ื’.
01:12
Members of the swarm interact only with their nearest neighbors
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ื—ื‘ืจื™ ื ื—ื™ืœ ืžืชืงืฉืจื™ื ืจืง ืขื ืฉื›ื ื™ื”ื ื”ืงืจื•ื‘ื™ื
01:16
or through indirect cues.
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ืื• ื“ืจืš ืกืžื ื™ื ืœื ื™ืฉื™ืจื™ื.
01:18
Each individual follows simple rules:
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ื›ืœ ืคืจื˜ ืขื•ืงื‘ ืื—ืจื™ ื›ืœืœื™ื ืคืฉื•ื˜ื™ื:
01:21
Travel in the same direction as those around you,
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ืœื ื•ืข ื‘ืื•ืชื• ื›ื™ื•ื•ืŸ ื›ืžื• ืืœื” ืฉืกื‘ื™ื‘ื•,
01:23
stay close,
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ืœื”ื™ืฉืืจ ืงืจื•ื‘,
01:24
and avoid collisions.
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ื•ืœื”ื™ืžื ืข ืžื”ืชื ื’ืฉื•ื™ื•ืช.
01:27
There are many benefits to traveling in a group like this.
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ื™ืฉ ื”ืจื‘ื” ืชื•ืขืœื•ืช ืœืžืกืข ื‘ืงื‘ื•ืฆื” ื›ื–ื•.
01:30
Small prey may fool predators by assembling into a swarm
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ื˜ืจืฃ ืงื˜ืŸ ืื•ืœื™ ื™ื˜ืขื” ื˜ื•ืจืคื™ื ืขืœ ื™ื“ื™ ื”ืฆื˜ื‘ืจื•ืช ืœื ื—ื™ืœ
01:33
that looks like a much bigger organism.
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ืฉื ืจืื” ื›ืžื• ืื•ืจื’ื ื™ื–ื ื’ื“ื•ืœ ื‘ื”ืจื‘ื”.
01:36
And congregating in a large group
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ื•ื”ืชืื—ื“ื•ืช ืœืงื‘ื•ืฆื” ื’ื“ื•ืœื”
01:38
reduces the chance that any single individual will be captured.
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ืžืคื—ื™ืชื” ืืช ื”ืกื™ื›ื•ืŸ ืฉืคืจื™ื˜ ื‘ื•ื“ื“ ื™ืœื›ื“.
01:42
Moving in the same direction as your neighbors
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ืชื ื•ืขื” ื‘ืื•ืชื• ื›ื™ื•ื•ืŸ ื›ืžื• ืฉื›ื ื™ื›ื
01:44
saves energy by sharing the effort of fighting wind or water resistance.
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ื—ื•ืกื›ืช ืื ืจื’ื™ื” ืขืœ ื™ื“ื™ ืฉื™ืชื•ืฃ ืžืืžืฅ ืฉืœ ื”ืชื ื’ื“ื•ืช ื”ืื•ื™ืจ ืื• ื”ืžื™ื.
01:49
It may even be easier to find a mate in a swarm.
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ื–ื” ืื•ืœื™ ื™ื”ื™ื” ืืคื™ืœื• ืงืœ ื™ื•ืชืจ ืœืžืฆื•ื ื‘ื ื™ ื–ื•ื’ ื‘ื ื—ื™ืœ.
01:53
Swarming can also allow groups of animals
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ื”ืชืื’ื“ื•ืช ืœื ื—ื™ืœ ืžืืคืฉืจืช ืœืงื‘ื•ืฆื•ืช ืฉืœ ื—ื™ื•ืช
01:55
to accomplish tasks they couldn't do individually.
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ืœื”ืฉื™ื’ ืžืฉื™ืžื•ืช ืฉื”ื ืœื ื™ื›ื•ืœื™ื ื›ื‘ื•ื“ื“ื™ื.
01:58
When hundreds or millions or organisms follow the same simple rules,
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ื›ืฉืžืื•ืช ืื• ืžืœื™ื•ื ื™ ืื•ืจื’ื ื™ื–ืžื™ื ืขื•ืงื‘ื™ื ืื—ืจื™ ืื•ืชื ื—ื•ืงื™ื ืคืฉื•ื˜ื™ื,
02:02
sophisticated behavior called swarm intelligence may arise.
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ื”ืชื ื”ื’ื•ืช ืžื•ืจื›ื‘ืช ืฉื ืงืจืืช ื‘ื™ื ืช ื ื—ื™ืœ ื™ื›ื•ืœื” ืœื”ื•ืคื™ืข.
02:07
A single ant can't do much on its own,
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ื ืžืœื” ื‘ื•ื“ื“ืช ืœื ื™ื›ื•ืœื” ืœืขืฉื•ืช ื”ืจื‘ื” ืœื‘ื“ื”,
02:10
but an ant colony can solve complex problems,
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ืื‘ืœ ืžื•ืฉื‘ืช ื ืžืœื™ื ื™ื›ื•ืœื” ืœืคืชื•ืจ ื‘ืขื™ื•ืช ืžื•ืจื›ื‘ื•ืช,
02:13
like building a nest
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ื›ืžื• ื‘ื ื™ื™ืช ืงืŸ
02:14
and finding the shortest path to a food source.
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ื•ืžืฆื™ืืช ื”ื ืชื™ื‘ ื”ืงืฆืจ ื‘ื™ื•ืชืจ ืœืžืงื•ืจ ืžื–ื•ืŸ.
02:18
But sometimes, things can go wrong.
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ืื‘ืœ ืœืคืขืžื™ื, ื“ื‘ืจื™ื ื™ื›ื•ืœื™ื ืœื”ืฉืชื‘ืฉ.
02:21
In a crowd, diseases spread more easily,
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ื‘ืงื”ืœ, ืžื—ืœื•ืช ืžืชืคืฉื˜ื•ืช ื™ื•ืชืจ ื‘ืงืœื•ืช,
02:24
and some swarming organisms may start eating each other if food is scarce.
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ื•ื›ืžื” ืื•ืจื’ื ื™ื–ืžื™ื ืฉืžืชืงื‘ืฆื™ื ืœื ื—ื™ืœื™ื ืื•ืœื™ ื™ืื›ืœื• ืื—ื“ ืืช ื”ืฉื ื™ ืื ื”ืื•ื›ืœ ืœื ื‘ื ืžืฆื.
02:30
Even some of the benefits of swarms, like more efficient navigation,
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ืืคื™ืœื• ืœื›ืžื” ืžื”ืชื•ืขืœื•ืช ืฉืœ ื ื—ื™ืœื™ื, ื›ืžื• ื ื™ื•ื•ื˜ ื˜ื•ื‘ ื™ื•ืชืจ,
02:33
can have catastrophic consequences.
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ื™ื›ื•ืœื•ืช ืœื”ื™ื•ืช ืชื•ืฆืื•ืช ื”ืจืกื ื™ื•ืช.
02:36
Army ants are one example.
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ื ืžืœื™ื ืฆื‘ืื™ื•ืช ื”ืŸ ื“ื•ื’ืžื” ืื—ืช.
02:38
They lay down chemicals called pheromones
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ื”ืŸ ืžืฉื—ืจืจื•ืช ื›ื™ืžื™ืงืœื™ื ืฉื ืงืจืื™ื ืคืจื•ืžื•ื ื™ื
02:40
which signal their neighbors to follow the trail.
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ืฉืžืื•ืชืชื™ื ืœืฉื›ื ื™ื”ื ืœืขืงื•ื‘ ืื—ืจื™ ื”ื ืชื™ื‘.
02:44
This is good if the head of the group is marching towards a food source.
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ื–ื” ื˜ื•ื‘ ืื ืจืืฉ ื”ืงื‘ื•ืฆื” ืฆื•ืขื“ ืœื›ื™ื•ื•ืŸ ืžืงื•ืจ ืžื–ื•ืŸ.
02:47
But occasionally the ants in the front can veer off course.
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ืื‘ืœ ืœืคืขืžื™ื ื”ื ืžืœื™ื ืžืงื“ื™ืžื” ื™ื›ื•ืœื•ืช ืœืกื˜ื•ืช ืžื”ืžืกืœื•ืœ.
02:51
The whole swarm can get caught in a loop following the pheromone trail
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ื›ืœ ื”ื ื—ื™ืœ ื™ื›ื•ืœ ืœื”ืœื›ื“ ื‘ืœื•ืœืื” ื‘ืžืขืงื‘ ืื—ืจื™ ื ืชื™ื‘ ื”ืคืจื•ืžื•ืŸ
02:55
until they die of exhaustion.
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ืขื“ ืฉื”ืŸ ืžืชื•ืช ืžืชืฉื™ืฉื•ืช.
02:58
Humans are notoriously individualistic, though social, animals.
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ืื ืฉื™ื ื™ื“ื•ืขื™ื ืœืฉืžืฆื” ื‘ืื™ื ื“ื™ื‘ื™ื“ื•ืืœื™ื•ืช ืฉืœื”ื ืœืžืจื•ืช ืฉื”ื ื—ื™ื•ืช ื—ื‘ืจืชื™ื•ืช.
03:03
But is there anything we can learn from collective swarm-based organization?
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ืื‘ืœ ื”ืื ื™ืฉ ืžืฉื”ื• ืฉืื ื—ื ื• ื™ื›ื•ืœื™ื ืœืœืžื•ื“ ืžืืจื’ื•ืŸ ืงื•ืœืงื˜ื™ื‘ื™ ืžื‘ื•ืกืก ื ื—ื™ืœ?
03:08
When it comes to technology, the answer is definitely yes.
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ื›ืฉื–ื” ืžื’ื™ืข ืœื˜ื›ื ื•ืœื•ื’ื™ื”, ื”ืชืฉื•ื‘ื” ื”ื™ื ื‘ื”ื—ืœื˜ ื›ืŸ.
03:12
Bats can teach drones how to navigate confined spaces without colliding,
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ืขื˜ืœืคื™ื ื™ื›ื•ืœื™ื ืœืœืžื“ ืžืœ"ื˜ื™ื ืื™ืš ืœื ื•ื•ื˜ ื‘ื—ืœืœ ืฆืจ ืžื‘ืœื™ ืœื”ืชื ื’ืฉ,
03:16
fish can help design software for safer driving,
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ื“ื’ื™ื ื™ื›ื•ืœื™ื ืœืขื–ื•ืจ ืœืชื›ื ืŸ ืชื•ื›ื ื•ืช ืœื ื”ื™ื’ื” ื‘ื˜ื•ื—ื” ื™ื•ืชืจ,
03:21
and insects are inspiring robot teams that can assist search and rescue missions.
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ื•ื—ืจืงื™ื ื ื•ืชื ื™ื ื”ืฉืจืื” ืœืฆื•ื•ืชื™ ืจื•ื‘ื•ื˜ื™ื ืฉื™ื›ื•ืœื™ื ืœืกื™ื™ืข ื‘ืžืฉื™ืžื•ืช ื—ื™ืœื•ืฅ ื•ื”ืฆืœื”,
03:27
For swarms of humans, it's perhaps more complicated
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ืœื ื—ื™ืœื™ื ืฉืœ ืื ืฉื™ื, ื–ื” ืื•ืœื™ ื™ื•ืชืจ ืžื•ืจื›ื‘
03:30
and depends on the motives and leadership.
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ื•ืชืœื•ื™ ื‘ืžื ื™ืขื™ื ื•ื‘ื”ื ื”ื’ื”.
03:33
Swarm behavior in human populations can sometimes manifest as a destructive mob.
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ื”ืชื ื”ื’ื•ืช ื ื—ื™ืœื™ื ื‘ืื•ื›ืœื•ืกื™ื•ืช ืื ื•ืฉื™ื•ืช ื™ื›ื•ืœื” ืœืคืขืžื™ื ืœื”ืชื‘ื˜ื ื‘ื”ืžื•ืŸ ื”ืจืกื ื™.
03:38
But collective action can also produce a crowd-sourced scientific breakthrough
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ืื‘ืœ ืคืขื•ืœื” ืงื•ืœืงื˜ื™ื‘ื™ืช ื™ื›ื•ืœื” ื’ื ืœื™ื™ืฆืจ ืคืจื™ืฆื•ืช ื“ืจืš ืžื“ืขื™ื•ืช ืžื‘ื•ืกืกื•ืช ืงื”ืœ
03:43
an artistic expression,
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ื”ื‘ืขื” ืืžื ื•ืชื™ืช,
03:45
or a peaceful global revolution.
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ืื• ืžื”ืคื›ื” ื’ืœื•ื‘ืœื™ืช ืฉืงื˜ื”.
ืขืœ ืืชืจ ื–ื”

ืืชืจ ื–ื” ื™ืฆื™ื’ ื‘ืคื ื™ื›ื ืกืจื˜ื•ื ื™ YouTube ื”ืžื•ืขื™ืœื™ื ืœืœื™ืžื•ื“ ืื ื’ืœื™ืช. ืชื•ื›ืœื• ืœืจืื•ืช ืฉื™ืขื•ืจื™ ืื ื’ืœื™ืช ื”ืžื•ืขื‘ืจื™ื ืขืœ ื™ื“ื™ ืžื•ืจื™ื ืžื”ืฉื•ืจื” ื”ืจืืฉื•ื ื” ืžืจื—ื‘ื™ ื”ืขื•ืœื. ืœื—ืฅ ืคืขืžื™ื™ื ืขืœ ื”ื›ืชื•ื‘ื™ื•ืช ื‘ืื ื’ืœื™ืช ื”ืžื•ืฆื’ื•ืช ื‘ื›ืœ ื“ืฃ ื•ื™ื“ืื• ื›ื“ื™ ืœื”ืคืขื™ืœ ืืช ื”ืกืจื˜ื•ืŸ ืžืฉื. ื”ื›ืชื•ื‘ื™ื•ืช ื’ื•ืœืœื•ืช ื‘ืกื ื›ืจื•ืŸ ืขื ื”ืคืขืœืช ื”ื•ื•ื™ื“ืื•. ืื ื™ืฉ ืœืš ื”ืขืจื•ืช ืื• ื‘ืงืฉื•ืช, ืื ื ืฆื•ืจ ืื™ืชื ื• ืงืฉืจ ื‘ืืžืฆืขื•ืช ื˜ื•ืคืก ื™ืฆื™ืจืช ืงืฉืจ ื–ื”.

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