Xperimental participants reviewed two research studies, one supporting and the other refuting the crime-deterring effectiveness of capital punishment. afterward, the opinions of those who initially favored the use of capital punishment became favorable toward its use. the opinions of those who initially opposed the use of capital punishment became favorable toward its use.

"More"  "Less"

Explanation:

experimental participants reviewed two research studies, one supporting and the other refuting the crime-deterring effectiveness of capital punishment. Afterward, the opinions of those who initially favored the use of capital punishment became more favorable toward its use. The opinions of those who initially opposed the use of capital punishment became less favorable toward its use.

productive most commonly means: achieving or producing a significant amount or result.

explanation:

productive can also mean:

these depend on how the word productive is used. most likely productive will mean   achieving or producing a significant amount or result.