BRAINLIEST!! PLEASE SOLVE THESE FOR ME. i have done 2 and 8 and i do not understand this at allPLEASE HELP EVEN WITH JUST ONE

Which element provides strength to the exoskeleton of clams and oysters

Ascience research group is testing a new type of plant food. one trial is conducted in a controlled experiment. the data from the trial show that the plant that received the new food grew faster than the control plant. the group announces that the new plant food makes plants grow faster. what is the main weakness in this scientific claim?

Which short-term environmental changes would a very small asteroid or comet impact on earth most likely cause? check all that apply. flooding extinction craters on surface changes in weather patterns death of organisms and populations