Environmental Issues — BIOLOGY STD 12 Science — Question

Two independent monohybrid crosses were carried out involving a tall pea plant with a dwarf pea plant. In the first cross, the offspring population had equal number of tall and dwarf plants, whereas in the second cross it was different. Work out the crosses, and explain giving reasons for the difference in the offspring populations.

Differentiate between : (i) Epicotyl and hypocotyl, (ii) Coleoptile and coleorrhiza, (iii) Integument and testa, (iv) Perisperm and pericarp

Define the following :
(i) Immunity (ii) Antigen (iii) Antibody (iv) Toxide (v) Immune system.

Describe the endosperm development in angiosperms.

Name the process of the rupture of Graafian follicle and the subsequent release of the egg from the ovary.

Match the Government initiatives to reduce pollution in Column I with the year in which they into effect in Column II.

S.No.	Column I	S.No.	Column II
A.	Air (Prevention and control of Pollution) Act	i.	1974
B.	Joint Forest Management water	ii.	1986
C.	Water (Prevention and Control Pollution)	iii.	1980
D.	Environment (Protection) Act	iv.	1981

How isolation of DNA is done from the cell?###Explain: separation and isolation of the genetic material (DNA).

What does an interaction between pollen grains and its compatible stigma result in after pollination? List two steps in sequence that follow after the process.

What are the various routes by which transmission of human immunodeficiency virus takes place?

Study the table showing the population interaction between species Z and Y respectively. Assign the appropriate +/- signs for A, B, D, E and respective interactions for C and F.

Species 'Z'	Species 'Y'	Name of Interaction
A	B	Mutualism
-	-	C
D	E	Parasitism
+	O	F