Answer:
Explanation:
A Pure bacterial culture must be grown in sterile tryptophan or peptone broth for 24–48 hours before performing the test. A sterile environment helps to avoid contamination.
When a test is conducted and it shows the presence of a red or red-violet color in the surface alcohol layer it means the result is positive
But when the colour is yellow it indicate negative reaction due to glucose fermentation.
A deviation from two color may also occur when we have an orange color. This colour change is due to the presence of methyl indole
When there is no color change this indicate No decarboxylase which is an enzyme needed for the fermentation reaction.
Color changes are indicator of how successful the reaction was.
PART 1
1. The answer is low frequency electromagnetic waves are able to go around obstacles due to their larger wavelengths. This characteristic of lower frequency waves is due to their ability to diffract around obstacles such as buildings and hills. Therefore, they transmit over long distances unlike high frequency electromagnetic waves.
2. One disadvantage is interference. Electromagnetic waves of the same frequency transmitted at the same time will interfere with one other and therefore the signal will be lost or scrambled. Other electromagnetic waves such as microwaves are affected (interfered with) by weather elements.
3. Analogue signals are continuous signals with wave-like properties while digital signals are discrete signals or pulse (ons (1s) and offs (0s) that represent bits). Analogue signal is represented by a sine-wave while digital signal is represented by discrete squares waves.
4. Digital signals are less immune to eavesdropping unlike analogue signals. Analogue signal is also more prone to distortion unlike digital signal. Digital signals transmit more data than analogue signals. Digital signal draw less energy to transmit compared to analogue signal.
5. Broadcasting of TV is nowadays using digital signals due to the high number of available channels. Computers and the interne utilize digital signaling to transmit data. Controls systems such as radar system also use aspects of analogue waves. Sensors also utilize analogue waves especially transducers such as seismology equipment.
PART 2
1. One way is by sending radio waves to probes sent out in space to give them commands during exploration. Radio telescopes also pick up naturally-occurring radio waves from space and analyze the data to make conclusions about space and the astronomical objects.
2. Radio waves are used in communication by transmitting data over long distances. One example is its use TV transmission. Another is through military defense of airspace. The radio waves are used to detect enemy intrusion into restricted airspaces using radar.
3. It is common that signal from the environment will be in analogue signal format. The conversion to digital signals allows for the digital equipment in the telescope to interpret and analyze the data. Telescopes prefer digital equipment because they consume less power, handle more data, and are less prone to intrusion, and distortion, hence more secure to analogue equipment.
Answer:
Virus can survive independently for many years.
Explanation:
independently because they cant live if they cant connect to the host cell
Answer:
Taj Mahal is slowly losing its white color because of pollutants from vehicles and industries around it. It is a result of chemical weathering. Polluted air contains a large amount of nitrogen and sulfur oxide released from the industries in the area.
These chemical comes down with the rain and called acid rain. This acid rain reacts with the marble which is made up of calcium carbonate thereby turning the Taj Mahal yellow.
These environmental pollution cause the oxidation of marble constituents from which Taj Mahal is made up of and are responsible for the chemical weathering of Taj Mahal.
When continents broke apart from Pangaea lots of different species got separated to different parts of the world. The animals and other living things had to have learned how to adapt to the different climates or they would die and go extinct.
