Sexual Reproduction In Flowering Plants — BIOLOGY STD 12 Science — Question

Biodiversity in living beings started about 3 billion years ago. Since then, new species are emerging on the earth and at the same time, their mass extinction is also taking place.
(a) How many phenomena of mass extinction have occurred on Earth and which extinction is in progress at present?
(b) How is the current phenomenon of extinction different from earlier occurrences and explain why.

Explain mechanism of pollination by water in marine water plants.###Explain - mechanism of pollination by water in Zostera###Explain mechanism of pollination by water in Sea-grasses.

State the diagnosis and treatment of AIDS.

Thermal power plants are inevitable in an industrial and densely populated country like ours. What harm do they do to the environment? Also mention any precautions that could be taken to save our environment.

Differentiate between albuminous and non-albuminous seeds, with an example for each.

An orchid plant is growing on the branch of mango tree. How do you describe this interaction between the orchid and the mango tree?

Name the improved characteristics of wheat that helped India achieve green revolution.

Humans derive countless direct economic benefits from nature. Explain.

List all the types of antibodies produced in our body. Among all, which antibodies are produced during?

1. Allergic reactions.
2. Transfusion reaction/ rejection.

Name the two techniques involved in controlled breeding experiments.