Human Reproduction — BIOLOGY STD 12 Science — Question

In a Polymerase Chain Reaction (PCR), give the temperature required for the steps:

1. Denaturation.
2. Annealing.
3. Extension, respectively.

Because 'health is the best wealth', we should make efforts to maintain good health. List any six ways to achieve good health.

Explain the experiment done by Miller regarding the origin and development of life. ###Make a clearly labeled picture of Stanley Miller's experiment. ###How the experiment done by Miller proved that the initial development of life happened from preexisting lifeless organic molecules.

Explain the laws that Mendel derived from his monohybrid crosses.

Mendel crossed plants that breed true for yellow seeds with plants that breed true for green seeds. All seeds in F-generation were yellow. Work out the inheritance involved in this cross by using symbols for each traits and state which trait was dominant?

What is polyembryony and how can it be commercially exploited?

The study of:

1. Fossils of dinosaurs.
2. Forelimbs of Cheeta, bat and human.
3. Thorns of Bougainvillea and tendril of Cucurbita shows that evolution of life forms has indeed taken place on earth. Explain.

Predation is usually referred to as a detrimental association. State any three positive roles that a predator plays in an ecosystem.​​​​​​