Erwin chargaff studied the dna of organismswithin a single species. chargaff discovered thatthe amount of adenine is about equal to the amountof thymine. which of these explains why the ratioof adenine to thymine is nearly 1: 1? a adenine and thymine pair with each other. b adenine binds with phosphates, while thymine binds with nitrates. c adenine and thymine are identical in chemical composition. d adenine bases contain a form of thymine.

hormones in blood stream

image: dtc.ucsf.edu

endocrine glands secrete hormones into the blood stream near them; the hormones then travel in our bloodstream until it reaches its destination, called a target cell, in distance parts of the body. in the target tissue, hormones lock onto the target’s plasma membrane, called the receptor site.

answer : haversian

[explanation: -(compact bone is organized as parallel columns, known as haversian systems, which run lengthwise down the axis of long bones. these columns are composed of lamellae, concentric rings of bone, surrounding a central channel, or haversian canal, that contains the nerves, blood vessels, and lymphatic system of the bone)]