Why does your upper arm have one bone and your lower arm have two bones?

According to bowlby which of the following is not required in order for infants to form healthy attachments with their parents

Transplant operations have become routine. one common transplant operation is for kidneys. the most dangerous aspect of the procedure is the possibility that the body may reject the new organ. there are several new drugs available for such circumstances and the earlier the drug is administered, the higher the probability of averting rejection. the new england journal of medicine recently reported the development of a new urine test to detect early warning signs that the body is rejecting a transplanted kidney. however, like most other tests, the new test is not perfect. in fact, 20% of negative tests and 10% of positive tests prove to be incorrect. physicians know that in about 33% of kidney transplants the body tries to reject the organ. if the new test has a positive result (indicating early warning of rejection), what is the probability that the body is attempting to reject the kidney?

What are the important influences on the study of personality today? what were some of the most important early impacts and biases on personality study?