### Question 2.1:
What percentage of urea was found in the urine?
Answer:
The percentage of urea found in the urine is 200%.
### Question 2.2:
Explain why there are no proteins in the filtrate.
Answer:
Proteins are typically large molecules, and during the filtration process in the kidneys, they are usually too large to pass through the filtration membrane of the glomerulus. The glomerulus acts as a selective barrier that allows smaller molecules like water, salts, and urea to pass through while retaining larger molecules such as proteins and blood cells in the bloodstream. Hence, proteins do not appear in the filtrate or urine, ensuring that essential proteins are retained in the body while waste products are excreted.
