Which of these statements best describes a double-replacement reaction? An element takes the place of another element in a compound.

Two or more substances react to form a single substance.

One compound breaks down into two or more simpler substances.

Two different compounds exchange positive ions and form two new compounds.

Researchers determine that the biodiversity in a woodland region is declining. they identify two major threats to the region's biodiversity, a method to address each threat, and the expected outcome of each method. this information is shown in the table. a) reforestation would not benefit many species because most forest species live on the ground. b) reforestation would take the longest time to be effective because trees take several years to grow. c) biological augmentation would benefit only a few species because is is typically not very effective. d) biological augmentation would take less time to ve effective because it targets the majority of prey species.