弱小

Many animals display maternal instincts only while their offspring are young and helpless.

许多动物在其幼崽弱小无法自助时都显出了母性本能。

Results showed that germination percentage of urediospore, uredium number and sporulation of challenge inoculation race were reduced after inoculation with weak virulent race.

试验结果表明，弱小诱导以降低挑菌系萌发率、堆数量、产量。