Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 46 to 50.

Not everybody recognizes the benefits of new developments in communications technology. Indeed, some people fear that text messaging may actually be having a negative ___(1)___ on your people’s communication and language skills, especially when we hear that primary school children may be at risk of becoming addicted to the habit. So widespread has texting become, however, that even pigeons have started doing it. ___(2)___, in this case, it’s difficult to view the results as anything but positive. Twenty of the birds are about to take to the skies with the task of measuring air pollution, each ___(3)___ with sensor equipment and a mobile phone. The readings made by the sensors will be automatically converted into text messages and beamed to the Internet where they will appear on a dedicated ‘pigeon blog’. The birds will also each have a GPS receiver and a camera to capture aerial photos, and researchers are building a tiny ‘pigeon kit’ containing all these gadgets. ___(4)___ bird will carry these in a miniature backpack,
apart, that is, from the camera, which will hang around its neck. The data the pigeons text will be displayed in the form of an interactive map, ___(5)___ will provide local residents with up-to-the-minute information on their local air quality.