Reproduction in Lower and Higher Plants — BIOLOGY STD 12 Science — Question

What is adaptive radiation? Explain with suitable example.

Expiration is called a passive process.

Enumerate the salient features of human genome.

In a person, Pars distalis part of the Pituitary gland is not producing hormones in sufficient quantity. Explain the effects it will produce with respect to the different hormones.###Give names and functions of hormones secreted by adenohypophysis.

Use this key for Questions A-D Key:

1. thymus gland.
2. spleen.
3. lymph node.
4. red bone marrow.

1. Causes differentiation of T-cells.
2. Purifies lymph.
3. Contains red pulp and white pulp.
4. Formation of granular and a granular leukocytes.

Observe the representation of genes involved in the lac operon given below:

1. Identify the region where the repressor protein will attach normally.
2. Under certain conditions repressor is unable to attach at this site. Explain.
3. If repressor fails to attach to the said site what products will be formed by z, y and a?
4. Analyse why this kind of regulation is called negative regulation.

What are the two groups of cells that work for specific immunity? Explain four unique features of specific immunity.

Nitrogen is a limiting nutrient in the agricultural system.

Describe in details different types of mycorrhizae.

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