A certain first order reaction has a half-life of 25.2 s at 20°C. What is the value of the rate constant k at 60°C if the activation energy, Ea=80 kJ mol-1 ?

The biome pictured above is found in areas such as kenya and south africa. the land is grass-covered with very few trees and gazelles and other grazers are common here. why does this biome have a low population of trees? a) large grazing animals destroy the trees. b) it is a deforested rainforest with poor soil. c) it has high temperatures and low precipitation. d) it has a long rainy season followed by flooding.

Why are radio observatories located in valleys far away from urban centers? a. to shield them from electromagnetic interference b. to avoid sound pollution c. to avoid disturbing people living in the city d. to shield them from water vapor

1. any body of surface water in which water is stored is a(n) aquifer reservoir channel floodplain 2.which of the following is a source of groundwater replenishment? seepage into springs infiltration from the surface evaporation all of the above 3. watersheds are bounded by points of high elevation called drainage basins. true false 4.non-native species can harm watershed environments by competing with native species for food. true false