Ielts reading question-type based tests true false not given matching headings

 
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Q4. Where do carbonates enter the oceans from? 
 
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Q5. How long did the oceans need to recover after the destruction of marine life by acidification 55 
million years ago? 
 
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Q6. Which businesses will suffer it reefs are damaged? 
 
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Q7. What type of creatures make their skeleton out of aragonite? 
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Welcome to Mr Aslanov’s Lessons 
QUESTION-TYPE BASED TESTS 
FunEnglishwithme [phone] 
TEST 4 – How Mobile Telephony Turned into a Health Scare 
The technology which enabled mobile phones was previously used in the kind of two-way radio 
which could be found in taxis and emergency vehicles. Although this was a great development, it was not 
really considered mobile telephony because it could not be used to dial into existing phone networks. It was 
known as simplex technology, operating on the same principles as a walkie-talkie, which required that a user 
press a button, meaning that only one person at a time could talk. Simplex meant that there was only one 
communication frequency in use at any one time. 
The first mobile phones to connect to telephone networks were often installed in cars before the hand-
held version came on the market and the revolution in mobile technology began. The first generation of 
mobile phones (called 1G) were large, heavy and analogue and it was not until the invention of the second 
generation (2G) in the 1990s that digital networks could be used the digital element enabled faster signaling. 
At the same time, developments in battery design and energy-saving electronics allowed the phones 
themselves to become smaller and therefore more truly mobile. The second generation allowed for text 
messaging too, and this began with the first person-to-person text message in Finland in 1993, although a 
machine-generated text message had been successfully sent two years earlier. 
None of this would have been possible without the development of duplex technology to replace the 
relatively primitive simplex technology of the first phase of mobile communication. In duplex technology, 
there are two frequencies available simultaneously. These two frequencies can be obtained by the principle 
of Frequency Division Duplex (FDD). To send two signals wirelessly; it is necessary to create a paired 
spectrum, where one band carries the uplink (from phone to antenna) and the other carries the downlink 
(from antenna to phone). Time Division Duplex (TDD) can achieve the same thing, but instead of splitting 
the frequency, the uplink and downlink are switched very rapidly, giving the impression that one frequency 
is used. 
For mobile telephony to work to its fullest potential, it needs to have a network through which it can 
relay signals. This network depends on base stations which send and receive the signals. The base stations 
tend to be simple constructions, or masts, on top of which are mounted the antennas, with the rapid increase 
in demand for mobile services. The infrastructure of antennas In the United Kingdom is now huge. 
Many thousands of reports have appeared claiming that the signals relayed by these antennas are 
harmful to human and animal health. The claims focus on the fact that the antennas are transmitting radio 
waves in microwave form. In some ways, public demand is responsible for the increase in the alleged threat 
to health. Until quite recently, voice and text messages were transmitted using 2G technology. A 2G mast 
can send a low-frequency microwave signal approximately 35 kilometres. Third generation (3G) technology 
allows users to wirelessly download information from the internet and is extremely popular. The difference 
is that 3G technology uses a higher frequency to carry the signals, allowing masts to emit more radiation. 
This problem is intensified by the need to have masts in closer proximity to each other and to the 
handsets themselves. Whatever danger there was in 2G signals is greatly multiplied by the fact that the 3G 
masts are physically much closer to people. Government authorities have so far refused to accept that there 
is a danger to public health, and tests carried out by governments and telecommunications companies have 
been restricted to testing to see if heat is being produced from these microwaves. According to many, 
however the problem is not heat, but electromagnetic waves which are found near the masts. 
It is believed that some people, though hot all, have a condition known as electro-sensitivity or 
electro-hypersensitivity (EHS), meaning that the electromagnetism makes them ill in some way. The actual 
health threat from these pulsed microwave signals is an area which greatly needs more research. It has been 
claimed that the signals affect all living organisms, including plants, at a cellular level and cause symptoms 
in people ranging from tiredness and headaches to cancer. Of particular concern is the effect that increased 
electromagnetic fields may have on children and the fear is that the negative effects on their health may not 
manifest themselves until they have had many years of continued exposure to high levels. Tests carried out 

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