Rainbow is produced when sunlight falls on drops of rain. Which of thefollowing physical phenomena are responsible for this?

1. Dispersion

2. Refraction

3. Internal reflection

Select the correct answer using the codes given below.

Many transplanted seedlings do not grow because

Which of the following statements is/are correct?

1. Viruses lack enzymes necessary for the generation of energy.

2. Viruses can be cultured in any synthetic medium.

3. Viruses are transmitted from one organism to another by biological vectors only.

Select the correct answer using the codes given below.

Which of the following leaf modifications occurs/occur in desert areas to inhibit water loss?

1. Hard and waxy leaves

2. Tiny leaves or no leaves

3. Thorns instead of leaves

Select the correct answer using the codes given below.

Mycorrhizal biotechnology has been used in rehabilitating degraded sitesbecause mycorrhiza enables the plants to

1. resist drought and increase absorptive area

2. tolerate extremes of pH

3. resist disease infestation

Select the correct answer using the codes given below.

Brass gets discoloured in air because of the presence of which of the following gases in air?

Which of the following is a non metal that remains liquid at room temperature?

Chlorophyll is a naturally occurring chelate compound in which central metal is

Which of the following is used in pencils?

Which of the following metals forms an amalgam with other metals?

Chemical formula for water is

The gas usually filled in the electric bulb is

Washing soda is the common name for

Quartz crystals normally used in quartz clocks etc. is chemically

Which of the gas is not known as green house gas?