Help chem. no rush...but will appreciate a quick answer
will mark brainliest

question is attached

A.(nh4)(2co3)is the correct answer 

Answerd. may include all of these are many definitions of bases: the  brønsted-lowry definition of acids and bases says that bases are proton acceptors.the arrhenius definition of acids and bases says that bases increase [oh⁻] in solution (thereby producing oh⁻ ions)the lewis definition of acids and bases says that bases donate electron pairs.therefore, the sensible answer is that a base may include all of the described characteristics.

Convection is da answer my dood

Burned piece of steel wool does not gain mass. so only d could be true.