Why is food separated into 4 food groups?

The world’s richest 20 percent of the population consume about what percentage of all goods and services in a given year?

Which behavior of an expectant mother is unhealthy

What is the function of reverse transcriptase in retroviruses? a) it uses viral rna as a template for dna synthesis.b) it converts host cell rna into viral dna.c) it translates viral rna into proteins.d) it uses viral rna as a template for making complementary rna strands.