Animal vectors are required for pollination in-
Cucumber
The correct option is D
Explanation of correct option
Explanation of incorrect option
Option A
The mulberry tree is often self-fertile. Pollination occurs through the wind.
Option B
Vallisneria is an aquatic freshwater plant where pollination occurs through the water.
Option D
The maize plant is usually cross-fertilized. Pollination occurs generally through the wind.
Final answer
Animal vectors are required for pollination in cucumbers.