How do Organisms Reproduce? — Science STD 10 — Question

A concave lens produces an image 20cm from the lens of an object placed 30cm from the lens. The focal length of the lens is:

A solar cooker may not cook food if.

Mineral acids are stronger acids than carboxylie acids because :

1. Mineral acids are completely ionised.
2. Carboxylic acids are completely ionised.
3. Mineral acids are partially ionized.
4. Carboxylic acids are partially ionized.

Single circulation i.e., blood flows through the heart only once during one cycle of passage through the body, is exhibited by :

A black strip of paper was clipped onto a destarched leaf in a potted plant to cover a part of the leaf. The plant was then exposed to sunlight for four hours, the paper strip was removed and the leaf was tested for starch.
When iodine solution was added:

In our country, there are attempts to increase the height of several existing dams like Tehri and Almati dams across Narmada. Choose the correct statements among the following that are a consequence of raising the height of dams:

1. Terrestrial flora and fauna of the area is destroyed completely.
2. Dislocation of people and domestic animals living in the area.
3. Valuable agricultural land may be permanently lost.
4. It will generate permanent employment for people.