In exploring for coal deposits, geologists sometimes look for fossil indicators: fossilized remains of Carboniferous plants. Which of the following combinations in a sample would suggest the presence of rocks that might bear coal beds?

1. mosses and liverworts, but no vascular plants
2. angiosperms and mosses
3. lycophytes and gymnosperms
4. lycophytes and tree ferns

During the carboniferous there is a proliferation of plants such as lycopodia and ferns. Theirs remains have generated large carbon deposits worldwide. These experimental plants reach their maximum richness and diversity during the Carboniferous (300-350 million years).

explanation:

for  example, forests have higher evapotranspiration than other ecosystems,  such  as grasslands, because of their deeper roots and greater leaf area. thus forests have a net moistening effect on the atmosphere and become a moisture source for downwind ecosystems.

a tetrad is the foursome during meiosis made by two homologous chromosomes that have each already replicated into a pair of sister chromatids.