33. Silicon carbide, Sic, has a structure similar to diamond. Boron nitride, BN, has a structure similar to graphite. Bronze is an alloy of copper.
Which statements about silicon carbide, boron nitride and bronze are correct?

I All of these substances are bonded covalently.

II All of these substances have high melting points.

III Boron nitride and bronze can conduct electricity in solid state but not pure
silicon carbide.

A II
B I, II
C I, III
D II, III

The answer is celsius 

Answerhave membrane-bound organelles;

Answer is: the equilibrium  shifts toward the reactants, to the left side of chemical reaction.it is because lead(ii) nitrate dissociates in water: pb(no₃)₂ → pb²⁺(aq) + 2no₃⁻(aq).according to lechatelier's principle, the position of equilibrium moves to counteract thechange (more lead cations, common ion), the position of equilibrium will move so that the concentration ofproducts decrease and concentration of reactants of chemical reaction increase.read more on -