What causes sounds that are lower than decibels?

9. what area of study applies scientific findings to create ways for solving problems or improving life? a biogeology b mathematics c manufacturing d engineering

Discuss the similarities and differences between whale flippers and tail flukes(*back fins, not the fish) and fish fins, using the scientific terms "homologous structures" and "analogous structures" in the discussion (5-7 sentences)

Maria wanted to grow a fern in her backyard. acting on a suggestion from a friend, she collected brown dots from the underside of a fern’s leaves and then potted them. after a few days, maria saw small fern leaves erupting from the pot. which statement explains this phenomenon?