Answer:
Softer? I hope this helps :)
Explanation:
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.
When sound waves hit a solid surface they either reflect, refract, or absorb.
Echo's are caused by the reflection of sound waves.
The first statement describes the environmental factor that affected the skipper butterflies.
When the birds became involved in the skipper butterflies ecosystem, they became a biotic environmental factor. The other answer choices are not environmental factors, but they are adaptations and examples of survival of the fittest.
Hope this helps! Good luck! :)
