Aperson who doesn't have enough calcium in his or her diet is at risk for developing bones that are weak and break easily. this condition is known as a. osteoporosis. b. crohn's disease. c. celiac disease. d. hemophilia.

The condition that causes weak / brittle bones from calcium deficiency is known as A) osteoporosis.

Many elderly people suffer from osteoporosis and that is why a fall as an older person may result in a broken bone. If a younger person had the same fall, their bones are not as likely to break.

Crohn's disease is a condition in the intestines in which the person suffers from chronically inflamed bowels. Celiac disease is the disease in which a person suffers great pain and cannot properly digest foods with gluten. Hemophilia is a blood disorder in which a person could bleed a lot from a small cut because the blood does not clot like the average person's blood does.

ANSWER: A) Osteoporosis

Hope this helps! :)

In this case your answer would be 

A - Osteoporosis

Blood transfusions were rarely done and often fatal; they were outlawed until the nineteenth century.