Receptor is on plasma membrane
a. peptide
b. steroid

a. Peptide hormone.

Explanation:

Hormones can be categorized into two groups based on their binding with the receptors. Some hormones bind to the membrane receptors because they cannot cross the phospholipid membrane. These hormones are peptide or protein hormones. Example is insulin hormone. They bind to exterior or membrane receptors and activate one or more secondary messengers for the physiological change. The other group of hormones are steroid and thyroid hormones which can easily cross the membranes. So they bind to the intra-cellular receptors or they enter nucleus and bind to the DNA for bringing the physiological change.

which fault and or fold did you find most difficult to diagram

osteogenesis imperfecta (oi) refers to a congenital ailment of bones. in the condition, the bones become brittle or fragile. this ailment is a general result of the defect or mutations in the genes (colia1 or colia2). this mutation results in imperfect collagen formation either in quantity or quality wise.  

there are eight kinds of oi defects, and each kind varies with certain distinctions in symptoms. the usual symptoms include frequent bone fractures, loss of hearing in infants, protruding eyes, discoloration of the white in the eyes, respiratory issues, loosening of the joints, short stature, and other symptoms.