Which of the following best explains how a tephra deposit forms

Airborne ash and rocks from a volcanic eruption remain suspended in the air for a long time

acts of terrorism occur globally. the united nations global counter-terrorism strategy was created in order to build adequate systems of support and solidarity with victims of terrorism. here´s a summary of the proposed key themes: the importance of giving victims a face and a voice; protecting their dignity; giving victims legal status and defending their legal rights; providing victims with medical, psycho-social and financial support; building solidarity with victims; improving media coverage of victims; and focusing on the link between victims and counter-terrorism efforts more generally.

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.