In humans, the yolk sac is the
site of origin for blood cells and primordial germ cells. The human yolk sac is
a membrane located outside the embryo and it is connected by a tube through the
umbilical opening to the embryo's midgut. The yolk sac serves as an early site
for the formation of blood and in time, is incorporated into the primitive gut
of the embryo.
45 guanine, 55 adenines
Every cytosine needs a guanine to be a pair, so that is 45 pairs right there.
100-45 = 55
There should be 55 adenine and thymine pairs to fill in the remaining bases
Answer:
Although more offsprings are produced by the process of external fertilization but the process of internal fertilization is more efficient as compared to external fertilization. This is because, in external fertilization, it is more difficult for the sperm to find the egg and fertilize it. Even after fertilization, it might be that the zygote gets eaten up by a predator. There are none such risks in internal fertilization. The zygote is protected during the internal fertilization which makes this process more efficient.
Answer:
C
Explanation:
The meninges are the membranous tissues that cover the spinal cord and the brain, providing support and protection to these organs. They are of three layers.
A) The Dura mater
B) The arachnoid mater
C) The pia mater
The Dura is the outermost meningeal layer and lies directly under the vertebral column bones and skull. The subdural space is the space between the Dura mater and the Arachnoid mater.
The Arachnoid mater lies in the middle of the Dura and Pia mater. Under the Arachnoid layer is the subarachnoid space which contains the cerebrospinal fluid. The cerebrospinal fluid acts as a shock absorber and a cushion to the brain and spinal cord.
The Pia mater lies under the subarachnoid space and directly on the spinal cord and brain and is highly vascularised.
The answers to this question are the following:
Base- pairing rule where RNA was made where the U strand being paired to A-strand and the C strand being paired to G-strand in transcription within the nucleus. This is done along with the intense strand in "DNA".
The answer in the first line is "Base-pairing rule" while in the second line is "DNA".
