One-year-old eunice is not overly fearful of strangers but she clearly prefers being held by her mother than by anyone else. her behavior best illustrates

The correct answer is secure attachment.

According to the attachment theory, children display different styles of attachments to their parents or primary caretakers, one of which is known as secure attachment style. This style of attachment in children is characterized by getting upset and distressed when separated from a parent, but feeling happy and comforted when being reunited with the parent. Secure attachment styles are associated with healthy and functional attachments later if life. 

The  ancient egyptians  who  built the pyramids  may have been  able  to move massive stone blocks across the desert by wetting the sand in front of a contraption  built  to pull the heavy objects