Choose the best answer:

1. (You're, Your) sister-in-law's car is parked in (its, it's)space.

Answer:
Your sister-in-law's car is parked in its space.

2. Four patients (was, were) sutured with 3-0 silk, and (its, it's) their responsibility to return for (their, they're) removal.
Answer:
Four patients were sutured with 3-0 silk, and it's their responsibility to return for their, removal.
Thanks

1. Correct

2. Remove the comma after "their" -- otherwise, it's OK.

Great job with the answers! Just a small correction for the second answer:

Four patients were sutured with 3-0 silk, and it's their responsibility to return for their removal.

In this sentence, "were" is the correct choice because it agrees with the plural subject "Four patients."

"It's" is the contraction of "it is" and is used to indicate possession or a characteristic. In this case, it indicates that the responsibility belongs to the patients.

"Their" is the correct possessive pronoun to show that the removal belongs to the patients.

Remember, when unsure about these grammar rules, you can always consult a grammar resource or refer to a grammar checker tool to check for correctness.