What forms when water supporting the roof of a cavern drains and the roof falls

Which element provides strength to the exoskeleton of clams and oysters

Milk production during breastfeeding is increased by the suckling of a newborn from his mother's nipple. this type of feedback mechanism best describes a positive or negative

In a vegetable garden 45 bean plants have been eaten by deer 5 are untouched what is the frequency of bean plants in the garden that have been eaten?