In Mendeleev’s Periodic Table, gaps were left for the elements to be discovered later. Which of the following elements found a place in the periodic table later ? [NCERT Exemplar Problems] (a) Germanium (b) Chlorine (c) Oxygen (d) Silicon

Wavelength of green light is

A) 400-450 nm

B) 500-550 nm

C) 660-720 nm

D) 720-800 nm

What is the difference between anaerobic & aerobic respiration? Name some organism that uses the aerobic mode of respiration?

What are the main components of our environment? Explain each of them briefly.

What are examples of hydrotropism plants?

Why is water liquid at room temperature?