Coralloids roots of ____have symbiotic association with `N_(2)`- fixing cyanobacteria.

Options

A. Pinus
B. Cedrus
C. Cycas
D. Ginkgo

Answer

C

Explanation

The coralloids roots of cycas are symbiotically associated with nitrogen fixing blue-green algae, anabaena cycadae and nostoc punctiforme. In the middle cortex of coralloid roots, a broad blue green zone occurs, which which is known as algal zone. coralloid roots are irregular negatively geotropic, dichotomosouly branched coral like roots which do not possess root hair and root caps.