Answer:
A. predation.
Explanation:
Predation is a type of ecological interaction in which one organism which is known as predator feeds upon another organism thereby killing it. The organism which is killed by predator is known as prey. In such interaction one organism is benefited while another one is harmed.
Brown bears of Alaska feed upon salmon. In order to so they have developed many ways which include waiting at the bottom of falls from where salmons pass by or standing at the bottom of the falls.
Answer:
Whether something is a molecule or not depends on the type of bond that is formed when its atoms join together. In general, electrons can be shared between atoms (a molecular bond) or electrons can be completely removed from one atom and given to another (an ionic bond). Molecules have molecular bonds.
I would say B.
Explanation: Peer review improves the quality of research papers.
Answer: The periodic table
Explanation: Demetri Mendeleyev is famous for developing the periodic table. He introduced it in 1869.
Answer :
(a) displacement reaction
(b) combination reaction
(c) disproportionation reaction
(d) displacement reaction
Explanation :
(a) The given balanced chemical reaction is,

This reaction is a single replacement reaction or displacement in which the the more reactive element (Fe) replace the less reactive element (H).
(b) The given balanced chemical reaction is,

This reaction is a combination reaction in which the two reactants molecule combine to form a large molecule or single product.
(c) The given balanced chemical reaction is,

This reaction is a disproportionation reaction in which the chemical species gets oxidized and reduced simultaneously. It is also considered as a redox reaction.
(d) The given balanced chemical reaction is,

This reaction is a single replacement reaction or displacement in which the the more reactive element (Ag) replace the less reactive element (Pt).