When problems with blood forming tissue are suspected, clinicians obtain tissue samples from the because the red bone marrow in this location is highly active in hematopoiesis.

Hip Bone

Explanation:

Hematopoiesis is a semi-solid tissue which is found in the cancellous or spongy portions of the bones.

In adult human, bone marrow is found in many bones of the body such as in the sternum, ribs and  bones of pelvis. On an average the 4 % of the whole body mass is bone marrow.

In case of any blood forming tissue problem the tissue sample are usually extracted from the pelvic bone because this is one of the actively participating regions in the body of adult.

hence, the correct answer is hip bone.

Hip bone.

Explanation:

The hematopoiesis is the process of formation of blood cells that are found in the spongy or cancellous portion of the body. Around  10¹¹–10¹² cells are produced daily in the body by hematopoiesis.

The bone marrow of adult human consists of the pelvis bones, ribs and sternum. The bone marrow includes the 4-5% body mass. The tissue are extracted from the pelvic or hip bone because this region actively participates in hematopoiesis.

Thus, the answer is hip bone.