1 point 50. Zinc does show variable
valency like d-block elements
because : *
O a) It is a metal
O b) It is low melting
c) Two melting are present in
outermost orbit
O d) d - orbital is complete.​

Ithink that the answer is b

Conservation efforts have been effective in "increasing the number of endangered species, reducing all the negative impacts of human activity, and preserving wildlife habitats".hope my answer has you : ) 

Hello.the answer is  hydrosphere, geosphere, and biosphere  have a nice day