by Brian Foden
Experts believe mosquitoes are possibly the deadliest creatures on Earth.
It may be hard to believe that some experts consider tiny mosquitoes to be the most dangerous creatures in the world. However, categorizing these insects _(1)_ dangerous animals
makes good
sense,
considering the fact that mosquito-
borne illnesses kill millions of people each year. The list of deadly diseases includes
malaria,
encephalitis,
West Nile virus,
yellow fever, and
dengue fever. In addition to
infecting humans with
life-threatening illnesses, mosquitoes also _(2)_ diseases to animals through
parasites and viruses.
_(3)_ only a few of the 3,500 species of mosquitoes
are capable of passing on diseases, the
blood-sucking nature of these
pests makes them
universally hated. Tens of millions of years of
evolution have turned mosquitoes into
adept hunters with a _(4)_ sense of survival. One way that mosquitoes have evolved to
track down potential meals of blood is through sensing carbon dioxide and
lactic acid, which are substances
emitted by
mammals and birds, from a range of up to 36 meters. These insects can also
detect heat and use visual _(5)_ to find
hosts to
feed on. _(6)_
visible clues, mosquitoes
are drawn to movement and people wearing clothing that is
in contrast to their
surroundings.
For those wondering why some mosquitoes risk _(7)_ blood from hosts who would gladly kill them, the reason is that the protein found in blood
acts as nourishment for producing eggs. In fact, only female mosquitoes suck blood. Males
seek out nectar and other sugars to consume.
1. (A) for (B) to (C) as (D) in
2. (A) transmit (B) recruit (C) surpass (D) intervene
3. (A) When (B) While (C) Unless (D) Until
4. (A) profitable (B) parallel (C) logical (D) keen
5. (A) restraints (B) sensations (C) thresholds (D) sanctions
6. (A) On the verge of (B) In terms of (C) In place of (D) For fear of
7. (A) to be drunk (B) drink (C) drinking (D) to drink
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