The first life form found on earth were mostly bacteria. "For the next 1.3 billion years (3.8 to 2.5 billion years ago), the Archean Period, first life began to appear and the world's landmasses began to form. Earth's initial life forms were bacteria, which could survive in the highly toxic atmosphere that existed during this time."
Hello, I figured that the question was missing its options so I went online to find them. Here they are:
All of the following are true of the thymus gland, except that:
A) activates B cells.
B) reaches its greatest relative size during the second year of life.
C) involutes after puberty.
D) produces T cells.
E) lies in the anterior mediastinum
Answer:
The correct answer is: A) activates B cells.
Explanation:
The thymus is a lymphatic organ that is located in the anterior superior mediastinum (a compartment in the thoracic cavity), in front of the heart, with the function to mature T cells (one of the types of lymphocytes, white blood cells very important for the functioning of the immune system).
The thymus is more active and bigger during childhood, when puberty hits it involutes and its functional tissue is replaced with adipose tissue (fat).
<u>B cells are not activated in the thymus, they mature in the bone marrow</u>.
The efferent (efferent means outgoing) arterioles are the blood vessels, which carry the blood away from the glomerulus. From the anastomotic capillaries into the cortex, which are also known as peritubular plexus the efferent arterioles bring the blood to the capillaries present in the medulla or vasa recta.
Hence, the correct answer is efferent arterioles.
