796. What is the use of a commutator? 
To change the direction of electric current 

797. Which is known as ‘the stress hormone’ in plants?
Abscisic acid 

798. What are the examples for the day-neutral plants? 
Tomato & cotton

799. Which plant hormone is found in the leaves & fruits?
Abscisic acid 

800. The biological nitrogen fixation occurs in roots of leguminous plants with a symbiotic association with ————– bacteria?
Rhizobium bacteria 

801. The plants that make their own food by the mechanism of photosynthesis is known in which name?
Autotrophs 

802. Few plants, especially fungi, cannot make their own food & depends on others. They are called as —————
Heterotrophs

803. Which macronutrient is essential for the enzyme activation, water balance, ion balance & stomatal opening in plants? 
Potassium 

804. Malacophily is the pollination by ————— in plants?
Snails 

805. The pollination by ants in plants is known as ————-
Myrmecophily 

806. Which part of the flower develops as pericarp of fruit after fertilizations? 

Nitrogen and hydrogen

808. When copper sulfate is mixed with lime, it is known as .
Bordeaux mixture

809. What is the most common use of Bordeaux mixture? 
Fungicide

810. Benzodiazepine is the most commonly used —————–
Psychoactive drug (Sleeping pill) 

811. What is used to change the direction of electric current?
Commutator 

812. A rocket works on the principle of conservation of ————
LinearMornentum

813. In surgery, metal pins are used for holding the broken bones together. It is made of ———-
Stainless steel 

814. Why the cloudy nights are warmer com¬pared to clear cloudless nights? 
Clouds reflect back the heat given off by Earth 

815. The plants which depend on other plants for mechanical support is known as. 
Epiphytes

816. Kilowatt Hour is the unit of. 
Energy

817. Where is the Atlas bone in the human body situated?
Neck 

818. Which instrument is used to record the growth of plants? 
Crescograph

819. Water pipes burst in severe winter at hill stations because of.
Water in the pipes expands on freezing 

820. Which gas helps for the artificial ripening of fruits? 
Acetylene

821. What is the source of energy in an artificial satellite?
Solar cells 

822. The energy from the Sun is received by Earth through. 
Radiation

823. The speed of a missile is mentioned in the unit of ————–
Mach 

824. Which parts of the body are connected by the eustachian tube? 
Ear&throat

825. Which device is used for detecting even feeble current? 
Galvanoscope

826. Name the acid in which the glass dissolves?
Hydrofluoric Acid 

827. Which is the only part of the human body that remains in the same size from birth to death?
Eyeballs 

828. Which element has the atomic number 100? 
Fermium

829. Which physical property does the colour of a star indicate?
Temperature

830. A vehicle silencer works on which prin¬ciple of the sound wave? 
Destructive Interference