When a resistance uniformly spreads against all the races of a pathogen, such resistance is known as –

Correct option is A

Correct option (a) Horizontal resistance
· Effective against all races of a pathogen.
· Controlled by many genes (polygenic).
· Durable and long-lasting resistance.
Other options:
· (b) Vertical resistance – Race-specific resistance.
· (c) Monogenic resistance – Controlled by a single gene, usually race-specific.
· (d) Oligogenic resistance – Controlled by few genes, not uniformly effective.
· (e) Incorrect.