Find a word to complete these sentences

Here are potential words to complete the sentences:

1a) At university, Catharine was a **student**. Needless to say, she passed all her exams with flying colors.
1b) This new **model** of the car can easily reach 100 kph in just under six seconds.
2a) The country has the largest number of national parks and **nature** reserves in the world and is an example for others to follow.
2b) Jennifer gave the **game** away when she began giggling behind his back. This made him suspicious.
2c) They were both sitting in the armchairs hunching over the desk and playing a **game** of chess.

Feel free to adjust the words based on the specific context!