The blood vessel that carries oxygenated blood from the placenta to the fetus is the: MCQ with Answer and Explanation

Explanation:
Cardiac muscle has striations and contracts involuntarily. Skeletal muscle is voluntary, smooth involuntary; myelin is produced by Schwann cells (PNS) and oligodendrocytes (CNS), not neurons.

Explanation:
Inspiration (inhalation) occurs when the intra-pulmonary pressure is less than the atmospheric pressure. This is achieved by the contraction of the diaphragm, which flattens and moves downwards, and the contraction of external intercostal muscles, which lift the ribs and sternum. This increases the thoracic volume and lung capacity, drawing air in. Expiration involves relaxation of these muscles.

Explanation:
Vaccination (immunization) involves administering killed or attenuated pathogens, or their antigens, to induce active artificial immunity without causing disease. It primes the immune system to produce memory cells. Antibiosis is inhibition by another organism, immunotherapy treats disease by modulating immune response, chemotherapy uses drugs against cancer or microbes.