D). Many different experiments are performed and repeated.
A shell is considered as biotic (living) because it is a hard, rigid covering of many animals such as snail, sepia, pila, turtles, sea urchins. A shell is protective outer layer of these soft bodied animals.
Answer:
Explanation:
Water in the lake (hydrosphere) seeps into the cliff walls behind the dam, becoming groundwater (lithosphere), or evaporating into the air (atmosphere). Humans (biosphere) harness energy from the water (hydrosphere) by having it spin turbines (lithosphere) to produce electricity.
Object permanence is the developmental milestone that must be reached before an infant experiences separation anxiety. It is used to describe the ability of a child to know that objects continue to exist despite the fact that they can no longer be perceived that is , seen or heard, touched, smelled, or sensed in any way. This milestone is developed through touching and handling objects by the infants.
