The vertebral column, also known as the spine or spinal column, is a series of bones called vertebrae that extend from the skull to the pelvis. It provides support for the body and protects the spinal cord. The five regions of the vertebral column, starting from the top and moving downwards, are:

1. Cervical: This region is made up of seven vertebrae and is located in the neck. The first two cervical vertebrae, the atlas and the axis, are specialized to allow for head movement.

2. Thoracic: This region is made up of twelve vertebrae and is located in the upper and middle back. The thoracic vertebrae are larger than the cervical vertebrae and articulate with the ribs.

3. Lumbar: This region is made up of five vertebrae and is located in the lower back. The lumbar vertebrae are the largest and strongest of the vertebrae.

4. Sacral: This region is made up of five fused vertebrae and is located in the pelvis. The sacrum forms the posterior wall of the pelvis and articulates with the hip bones.

5. Coccygeal: This region is made up of four fused vertebrae and is located at the base of the vertebral column. The coccyx, or tailbone, provides atachment points for muscles and ligaments.

Ribosomes are small, spherical structures found in all living cells, including bacteria, archaea, and eukaryotes. Their primary function is to synthesize proteins using the genetic information stored in the cell's DNA. Ribosomes are composed of two subunits, one large and one small, that come together during protein synthesis.

Ribosomes read the genetic information stored in mRNA (messenger RNA) and use this information to assemble amino acids in the correct order to form a protein. The ribosome moves along the mRNA, adding one amino acid at a time to the growing protein chain until it reaches the end of the mRNA and the protein is complete.

Proteins are essential for a wide variety of cellular functions, including catalyzing chemical reactions, providing structural support, and transporting molecules across cell membranes. Therefore, ribosomes play a critical role in the overall function and survival of a cell.

Transcription is the process by which DNA is copied into RNA. During transcription, the DNA molecule unwinds and RNA polymerase reads the DNA sequence and synthesizes a complementary RNA molecule using the DNA as a template.

Ligaments are tough bands of fibrous ssue that connect two bones together in a joint. They provide stability and support to the joint, prevenng excessive movement and helping to maintain proper alignment of the bones.

One of the main funcons of the respiratory system is to facilitate the exchange of gases between the body and the environment. During inhalaon, air enters the lungs and oxygen is absorbed into the bloodstream. During exhalaon, carbon dioxide is removed from the body and expelled into the environment.

Red blood cells, also known as erythrocytes, play a crucial role in the circulatory system, primarily by facilitating the transportation of oxygen to body tissues. The other choices are also explained below:

A. Facilitation of gas exchange in the alveoli: While gas exchange occurs in the alveoli of the lungs, it is primarily carried out by the respiratory system and involves the exchange of oxygen and carbon dioxide between air and blood. Red blood cells do not directly participate in this process.

B. Regulation of blood pH through the release of bicarbonate ions: The regulation of blood pH is mainly maintained by the bicarbonate buffering system, which involves the action of the respiratory and renal systems. Red blood cells do play a minor role in transporting carbon dioxide, which can indirectly influence pH, but it's not their primary function.

D. Synthesis of clotting factors in response to vascular injury: Clotting factors are primarily produced by the liver and are involved in the blood clotting process to prevent excessive bleeding. Red blood cells are not directly responsible for synthesizing these factors.

A double-blind study is a research design in which neither the participants nor the researchers know which group participants are assigned to. This is done to minimize bias and ensure that the results of the study are as objective as possible. In a double-blind study, the treatment and control groups are randomly assigned, and the participants and researchers are unaware of which group each participant is assigned to.

Option a) is an example of a randomized controlled trial, which is a common research design, but it is not necessarily double-blind.

Option b) is an example of an open-label study, in which both the participants and the researchers know which group each participant is assigned to.

Option c) is an example of a single-blind study, in which the participants do not know which group they are assigned to, but the researchers do.

• A. Sarcoplasmic Reticulum → A specialized endoplasmic reticulum in muscle cells that stores and releases calcium for muscle contraction. ❌
• B. Muscle Fiber → Another name for a muscle cell, which is a long, cylindrical, multinucleated cell that makes up muscle tissue. ✅
• C. Sarcolemma → The cell membrane of a muscle fiber, which surrounds the muscle cell. ❌
• D. Myofilament → Protein structures (actin and myosin) within a muscle fiber that are responsible for contraction. ❌

The three germ layers that form during embryonic development are the ectoderm, mesoderm, and endoderm. The ectoderm is the outermost layer, and it gives rise to the skin, hair, nails, and nervous system. The nervous system develops from a specialized region of the ectoderm called the neural plate, which invaginates to form the neural tube. The neural tube ulmately gives rise to the brain and spinal cord, which make up the central nervous system, as well as the peripheral nervous system. The endoderm gives rise to the lining of the digesve and respiratory tracts, while the mesoderm gives rise to the musculoskeletal system, circulatory system, and several other organs. The exoderm is not a germ layer and does not exist during embryonic development.

• Frontal Plane (Coronal Plane) → Divides the body into front (anterior) and back (posterior) halves. ❌
• Transverse Plane → A horizontal plane that divides the body into upper (superior) and lower (inferior) halves. ✅
• Sagittal Plane → Divides the body into left and right halves. ❌
• Coronal Plane → Another name for the Frontal Plane, which divides the body into front and back. ❌