(a)The ____ (i) ____ portal system is crucial for ____ (ii) ____ nutrients absorbed from the gastrointestinal (a) tract. It transports these substances directly to the ____ (iii) ____ for processing. This system helps in detoxifying harmful substances, thereby playing a vital role in ____ (iv) ____ . It also regulates the levels of various substances like ____ (v) ____ in the blood.
(b)In the ____ (i) ____ blood group system, blood types are determined by the presence or absence of certain ____ (ii) ____ on the surface of ____ (iii) ____ blood cells. The ____ (iv) ____ factor, another important blood antigen, can be either ____ (v) ____ , leading to further classification.