In the following passage some words have been deleted. Fill in the blanks with the help of the alternatives given.
Passage:

Fundamentally, all human beings possess a combination offixed inherited traits. All individuals possess the .............(1) highly developed nervous system, backbones, erect posture, hair,etc. Therefore, ...........(2) among human beingsarise only in ..............(3) changesofthis basic pattern. Racial differences ..............(4) one of the finest distinctions and are based only on ..........(5) slight differences.