What protects the inside of a cell from the outside world? cell membrane nucleus cytoplasm dna

Based on the results of this study, what questions remain unanswered? how can these questions guide future research

Out of the seven main animal groups (fish, mammals, birds, insects, reptiles, amphibians, and arachnids), how many contain members with internal backbones? a. 5 b. 3 c. 7 d. 1

What is the difference between an igneous, sedimentary and metamorphic rock