Respiration and Circulation — BIOLOGY STD 12 Science — Question

Rose plants produce large, attractive bisexual flowers but they seldom produce fruit. On the other hand, Lady’s finger produces plenty of fruits. Analyse the reasons for failure of fruit formation in rose.

Discuss the role of lymphoids in the immune response. Explain the different types of lymphoid organs giving two examples of each type in human.

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

Distinguish Between: Dominant characters and Recessive characters.

Smita was working in a garage with the doors closed and automobiles engine running. After some time she felt breathless and fainted. What would be the reason? How can she be treated
OR
While working with the car engine in a closed garage, John suddenly felt dizzy and fainted what is the possible reason?

With the help of a neat labelled diagram, describe the internal structure of human heart.

Answer the following questions:
Draw a schematic labelled diagram of a fertilised embryo sac of an angiosperm.

Would you consider wings of butterfly and bat as homologous or analogous and why?

Name three species of fungi that cause ringworm. Mention the symptoms of this disease?