1. compare and contrast a food chain and a food web. 2. explain the purpose of the arrows.

In comparison they both show feeding relationship in an ecosystem.
In contrast, a food chain is a simple linear feeding relationship while a food web is a complex feeding relationship.

2) The arrows is to show the direction of the feeding relationship

The main role of dna in the  cell is the long-term storage of information. it is often compared to a blueprint, since it contains the instructions to construct other components of the  cell, such as  proteins  and rna molecules.the main function of rna is to carry information of amino acid sequence from the genes to where  proteins  are assembled on  ribosomes  in the  cytoplasm. mark brainliest, my work is good.