Explain why sexual reproduction in angiosperms is said to take place through double fertilization and triple fusion. Also draw a labelled diagram of embryo sac to explain the phenomena.

Explain why fusion inside stars can take place between nuclei having mass number smaller than that of iron?

Answer the following questions With a neat labelled diagram, explain twinkling of a star . Also explain why a planet does not twinkle.

Answer the following questions : With a neat labelled diagram, describe the pattern of magnetic lines of force due to a current through a circular loop. Also explain how the magnetic field depends on the number of turns (n) in the loop.

Choose the correct option from the bracket and explain the statement giving reason: (oxidation, displacement, electrolysis, reduction, zinc, copper, double, displacement, decomposition ) When electric current is passed through acidulated water _ of water takes place.

Veena observes that during winter setting of milk into curd takes more time while during summer, the same process happens faster. She asks about this difference in time taken to her elder sister. She also asks her sister about why certain reactions occur rapidly while others occur slowly. Her sister explains her about the various factors that affect the rate of chemical reactions. Based on the above scenario, answer the following questions. The reaction of aluminum metal with dilute hydrochloric acid takes place faster as compared to zinc metal. What could be the reason for this difference?

Draw a labelled diagram of the L.S. of anatropous ovule and list the components of embryo sac and mention their fate after fertilization.