Mmmm I don't know much about biology. Bs atw83 bio itself as a bachelor degree limits you to academia. While pursuing a Masters and PhD in a more specific field in bio, like cellular biology, gives you more chance to end up doing research and many other opportunities.
Seriously tho, why chemistry? Very little job opportunities in Saudi?
Not really. There is KAUST, Sabic, Schlumberger, Aramco and many other companies. Saudi now has sufficient number of engineers and trying to recruit researchers and become less dependent on oil. Therefore, I think we're undergoing on a less dependency on engineers phase.