Question

1. Fill in the blanks.
(a)
algae fix nitrogen directly from air to enhance fertility of soil.
(b) Milk can be preserved by
(c) Cholera is caused by
(d) mosquito causes dengue disease in humans.
(e) is used in the process of fermentation.​

Answer 1

✬ ANSWER ✬

a.) Blue green algae fix nitrogen directly from air to enhance fertility of soil.

b.) Milk can be preserved by Pasteurisation or by adding a few drops of HCHO solution.

c.) Cholera is caused by a bacterium called Vibrio cholerae.

d.) Aedes aegypti mosquito causes dengue , yellow fever , disease in humans.

e.) Yeast or sugar is used in the process of fermentation.

_________________________

• The process by which atmospheric nitrogen is converted in ammonia (NH³) is called nitrogen fixation.

• The process of heating the milk at high temperature and quickly cooling down is called pasteurisation. Most bacteria in milk and other liquids can be killed during this process.

• Cholera can be spread by contaminated water or food. It's symptoms are vomiting, abdominal pains etc. Vaccination can prevent this.

• When an mosquito bites an infected person , it carries microbes with it and transfers to any healthy person by biting.

• The process of breakdown of substances by fungi and bacteria usually leading to the production of Co2 and Alcohol.