Answer
(a) All species concepts can be applied to both asexual and sexual species except for the biological species concept, which only applies to sexually reproducing species.
(b) The morphological species concept would be the easiest to apply in the field.
Work Step by Step
(a) Only the criteria for the biological species concept specifies reproductive standards.
(b) In the field, morphological differences between organisms are the easiest data type to collect as it largely requires only simple observation. That makes the morphological species concept the most useful in this scenario, though relying on it alone may not provide a complete or accurate picture.
