You cannot see a microorganisms without using a Microscope. You also cannot taste or smell microorganisms such as bacteria in contaminated food.

Here Grass is to Erosion and whereas Dam is to Water.

Since Grass prevents Erosion similarly Dam prevents Water flow.

Hence, Grass : Erosion :: Dam : Water.

Here the given words Careful and Cautious are related in such a way that they are Synonyms of each other.

Therefore, Similarly Boastful is synonym to the word Arrogant.

Happily and Humble are Antonyms of Boastful and Surprisingly is the word not related to Boastful in any way.

So, Careful is to Cautious as Boastful is to Arrogant.

1. Lichens are plants that grow in exposed places such as rocks or tree bark.

2.  Lichens are widely used as environmental indicators or bio-indicators. They can be used as air pollution indicators, especially of the concentration of sulfur-di-oxide in the atmosphere.  

3. They need to be very good at absorbing water and nutrients to grow there.

A change to the Constitution is called as An Amendment.

An Amendment ::

An Amendment is ratified after two-thirds of the House and Senate approve of the proposal and send it to the states for a vote. That Convention can propose as many amendments as it deems necessary. Then, three-fourths of the states must affirm the proposed Amendment.

The Given number series 3, 6.5, 14, 29, 64, 136 follows a pattern that

3

3 x 2 + 0.5 = 6.5

6.5 x 2 + 1 = 14

14 x 2 + 2 = 30 ≠29

30 x 2 + 4 = 64

64 x 2 + 8 = 136

Thus the wrong number in the series is 29

Let the total distance of the journey of a man = d kms

Now, the average speed of the entire journey = dd120 + d120 + d40 = 24 kmph.

The Bacteria that causes Food Borne illness are called Food Borne Pathogens. Most of the pathogens are mesophilic in nature, optimum temperature may be around 20-45 degree celsius. This range of temperatures is often called the "Danger Zone." Dry foods do not support the growth of bacteria.

In order to kill pathogenic bacteria you need temperatures above 74ºC. Temperature is the easiest factor to control in order to prevent bacterial growth.