Plant Water Relation — BIOLOGY STD 12 Science — Question

Give reasons : Valves are present in veins.

Give one example of autosomal recessive disorder.

In the biosphere immense biological diversity exists at all levels of biological organisation. Explain any two levels of biodiversity.

Suggest four advanced ex-situ methods to conserve threatened biodiversity.

Mention the relationship between concentration of luteinising hormone and maintenance of endometrium in the human uterus.

Make a chart (with diagrammatic representation) showing a restriction enzyme, the substrate DNA on which it acts, the site at which it cuts DNA and the product it produces.

Explain the following terms with reference to ecological succession : Xerosere.

List the symptoms of Ascariasis. How does a healthy person acquire this infection?

Name the two techniques involved in controlled breeding experiments.

Explain different biosafety issues which may arise due to genetically modified (GM) organisms.