They respond to danger by diving rather than flying, and are in any case much less wary than ducks. Extant species range in size from the least grebe, at 120 grams (4.3 oz) and 23.5 cm (9.3 inches), to the great grebe, at 1.7 kg (3.8 lbs) and 71 cm (28 inches).hey respond to danger by diving rather than flying, and are in any case much less wary than ducks. Extant species range in size from the least grebe, at 120 grams (4.3 oz) and 23.5 cm (9.3 inches), to the great grebe, at 1.7 kg (3.8 lbs) and 71 cm (28 inches).
Noun. 1. productivity-the quality of being productive or having the power to produce. productiveness. fruitfulness, fecundity-the quality of something that causes or assists healthy growth.
productivity - (economics) the ratio of the quantity and quality of units produced to the labor per unit of time. economic science, economics, political economy - the branch of social science that deals with the production and distribution and consumption of goods and services and their management.