Which of the following statement best describes endocrine glands?

After birth, blood is primarily produced in the red bone marrow of the infant. Red bone marrow is a spongy tissue found in the hollow centers of certain bones, such as the skull, ribs, pelvis, and long bones of the arms and legs. Red bone marrow is responsible for producing red blood cells, white blood cells, and platelets.

In adults, some of the blood production shifts to other organs such as the spleen and liver. However, in infants, the red bone marrow is the main site of blood cell production until about 5 years of age when it begins to gradually transition to the other organs.

Intramembranous ossification is a process of bone formation in which bone tissue forms directly within mesenchymal (undifferentiated) connective tissue membranes. This process is responsible for the formation of the flat bones of the skull, including the frontal, parietal, occipital, and temporal bones.

Long bones of the arms and legs, bones of the pelvic girdle, and vertebrae are formed by endochondral ossification, a different process of bone formation in which bone tissue replaces hyaline cartilage.

The left ventricle of the heart normally has the thickest wall, which is composed mainly of cardiac muscle tissue (myocardium). The left ventricle has to generate enough force to pump oxygen-rich blood to the rest of the body through systemic circulation, which requires greater muscular effort than the right ventricle, which pumps blood only to the lungs via pulmonary circulation. The thickness of the left ventricular wall ensures that it can withstand the pressure required to generate this forceful contraction.

The ABCD rule is a mnemonic used to identify the characteristics of melanoma, which is a type of skin cancer. The leters stand for:

A -Asymmetry: One half of the mole or lesion does not match the other half.

B - Border irregularity: The edges are ragged, notched, or blurred.

C - Color: The color is not uniform and may include different shades of brown or black, or sometimes patches of pink, red, white, or blue.

D - Diameter: The size of the mole or lesion is greater than 6 mm (about the size of a pencil eraser), although melanomas can sometimes be smaller.

This rule is not as useful in detecting other types of skin cancer, such as squamous cell carcinoma, basal cell carcinoma, or sarcoma, as they tend to have different characteristics. However, any new or changing mole or lesion on the skin should be examined by a dermatologist to determine if it is cancerous.