MODEL PAPER 9 — BIOLOGY STD 12 Science — Question

Describe the advantages for keeping the ecosystems healthy.

What are biofertilisers? Name the categories of organisms used as biofertilisers with an example for each. How do they function in organic farming?

It has often been seen that phenotype of F1 offspring resembles to both the parents. Justify your by taking the example of inheritance of ABO blood group in human being.

Fill in the blanks in the different column of the table given below:

Disease	Casual organisms	Medium of transfer	Symptoms
Amoebiasis	Entamoeba histolytica	a	Diarrhoea
Typhoid	b	Contaminated food	Sustained high fever
c	Plasmodium	Bite of infected female Anopheles mosquito	Chill and high fever
Pneumonia	Steptococcus	d	Fever and cough

How many types of natural selection are there? Discuss each type with a suitable example.

What develops into a microspore mother cell in a flower? Trace the development of this cell into a pollen grain which is ready for germination. Draw a labelled figure of a mature pollen grain.

Sakshi's father announced that the children are going to spend this weekend with their grandparents. During the journey, Sakshi saw some farmers who were spraying agrochemicals in their field. She requested her father to stop them. Her father praised her and contacted the farmers. He explained the side effects of such agrochemicals. He also suggested them to use biopesticides and biofertilisers instead of such chemicals. The farmers gave up spraying agrochemicals.

1. What did Sakshi's father explain to the farmers?
2. What are agrochemicals?
3. Why are biofertilisers or biopesticides preferred to chemical fertilisers or pesticides?
4. What values did Sakshi promote?

Draw a labelled diagram of the sectional view of a mature pollen grain of angiosperms. Explain the function of any two of its parts.

What is integrated waste water management? Discuss its advantage.