Please provide a legitimate answer and provide an explanation for the question below.

Describe how one system of the body is used differently once a baby is born compared to when the baby was a fetus.

. Identify the process that triggers the initial surge of nitrogen excretion,

The reason for this is because of the gluconeogenesis ,(in the liver and cortex of the kidney) which make up for the  reduction in glucose blood level, from rapid catabolism to glucose at the beginning of fasting, by breaking down protein to glucose in the liver. Therefore excess Nitrogen is produced as the byproducts of amino acids catabolism.

Physiologically the mammalian brain prefers the keto bodies supply from fatty acids catabolism from gluconeogenesis compare to protein. These water solube subtances cross the BBB to  reach the brain the CNS substituting for glucose. Thus as more fatty acids is converted to ketobodies at faster rate, the brain gets adapted to this, and therefore catabolism of amino acids drops, hence Nitrogen concentration in the blood drops.

However, with exhaustion of Glycogen and fatty acid, catabolims of amino acids resumes. therefore, more amino acids are broken down, and Nitrogen build up in the Urine for excretion.

Explanation: