Unit+Two-Page57


 * Task Seven **
 * Insert the article a or an ** ** where necessary in the following definitions. **


 * 1) Helium is gas with atomic number of 2. (a gas)
 * 2) El Nino is disruption of ocean-atmosphere system in tropical pacific having important consequences for weather worldwide. (a disruption)
 * 3) White wharf is star that is unusually faint given its extreme temperature. (a star)
 * 4) Rice is cereal grain that usually requires subtropical climate and abundance of moisture for growth. (a cereal)
 * 5) Transduction is technique in which genes are inserted into host cell by means of viral infection. (a technique)
 * 6) In seismology, liquefaction is phenomenon in which soil behaves much like liquid during earthquake. (a phenomenon)
 * 7) Disability is physical or mental impairment that substantially limits one or major life activities such as seeing, hearing, speaking, walking, breathing, performing manual tasks, learning, caring for oneself, and working. (a physical)
 * 8) Hydrothermal vent is crack in ocean floor that discharges hot (350_400), chemically enriched fluids and provides habitat for many creatures that are not found anywhere else in ocean. (a crack)


 * Task Eight **


 * Edit the following by reducing the relative clauses where possible. **
 * 1) Aluminum is a lightweight metal that is often used for high tension power transmission= Aluminum is a lightweight metal often used for high tension power transmission.
 * 2) Heat is a form of energy which can be transmitted through solid and liquid media by conduction. (it can’t be reduced because of the modal auxiliary)
 * 3) A brake is a device that is capable of slowing the motion of a mechanism= A brake is a device capable of slowing the motion of a mechanism.
 * 4) A dome is generally a hemispherical roof which is on top of a circular, square, or other-shaped space= A dome is generally a hemispherical roof on top of a circular, square, or other-shaped space.
 * 5) Snow is a form of precipitation which results from the sublimation of water vapor into solid crystals at temperatures below 0= Snow is a form of precipitation resulting from the sublimation of water vapor into solid crystals at temperatures below 0.
 * 6) An antigen is a substance which causes the formation of antibodies, the body’s natural response to foreign substances=An antigen is a substance causing the formation of antibodies, the body’s natural response to foreign substances.
 * 7) A piccolo is a small flute that is pitched an octave higher than a standard flute= A piccolo is a small flute pitched an octave higher than a standard flute.
 * 8) Membrane permeation is a separation process that involves the selective transport of gas molecules through a permeable polymeric film= Membrane permeation is a separation process involving the selective transport of gas molecules through a permeable polymeric film.
 * 9) A Catalyst is a substance that can speed up the rate of a chemical reaction without changing its own structure. (it can’t be reduced because of the modal auxiliary)
 * 10) A black hole is a celestial body which has approximately the same mass as the sun and a gravitational radius of about 3km= A black hole is a celestial body with approximately the same mass as the sun and a gravitational radius of about 3km.


 * Task Nine **
 * Complete the following definitions by inserting an appropriate preposition. **


 * 1) A thermometer is an instrument (by means of) which temperature can be measured.
 * 2) Photosynthesis is a process (by) which sunlight is used to manufacture carbohydrates from water and carbon dioxide.
 * 3) A credit bureau is an organization (in) which businesses can apply for financial information on potential customers.
 * 4) An anhydride is a compound (by) which the elements of water have been removed.
 * 5) An eclipse is a celestial event (on) which one body such as star, is covered by another, such as a planet.
 * 6) An axis is an imaginary line (in) which a body is said to rotate.
 * 7) Large diameter tunnels are linear underground structures (in) which the length is much larger than the cross-sectional dimension.
 * 8) Demographers are concerned with changes in population size and the degree (of) which fertility (i.e., births), mortality (i.e., deaths), and migration (i.e., movement into and out of an area) contribute to these changes.
 * 9) The ease (by) which a fraudulent business operation can set up shop on the Internet is unfortunately high.
 * 10) “ Hoteling “ is a new type of office design (through) which employees who mostly work at home or in the field are not given permanent offices but ,rather, shared, temporary space as needed.