70. There has been a considerable fall in the value of sterling in the past week.
VI. ERROR IDENTIFICATION (10 marks)
Water scarcity is fast becoming one of the major limited factors
limiting
in world crop production. In many areas, poor agricultural
………
practices have led to increasing desertification and the loss of
………
formerly arable lands. Consequently, those plants species that are
well adapted with survival in dry climates are being looked at for
to
an answer in development more efficient crops to grow on
developing
marginally arable lands.
Plants use several mechanisms to ensure their survival in desert
environments. Some involve pure mechanical and physical
purely
adaptations, such as the shape of the plant’s surface, smaller
leafed size, and extensive root systems. Some of the adaptations
leaf
are related to chemical mechanisms. Many plants, such as cacti,
have internal gums and mucilages which give them water-
Another
retaining properties. Other chemical mechanism is that of the
epicuticular wax layer. This wax layer acts as an impervious
of
cover to protect the plant. It prevents excessive loss from internal
moisture. It also protects the plant from external aggression,
which can come from inorganic agents such as gases, or organic
agents which include bacteria ant plant pets.
Researchers have proposed that synthetic waxes with similar
protective abilities could be prepared based on knowledge of
is
desert plants. If is successfully developed, such a compound
increase
could be used to greatly increasing a plant’s ability to maintain
health in so adverse situations as inadequate water supply,
such
limited fertilizers availability, attacked by pets, and poor storage
after harvesting.
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