7) Why are fuel cells considered a "clean" energy source? *

Hydrogen can be considered as a clean energy carrier similar to electricity. Hydrogen can be produced from various domestic resources such as renewable energy. ... Power generation,a hydrogen fuel cell generates electricity and gives off heat and water.

2positives of biotechnology: 1. plants have become more resistant to viruses and other communicable pests.2. with the of biotechnology, we have been able to produce better tasting fruits as well as vegetables.2 negatives of biotechnology: 1. biotechnology poses a number of environmental threats. genetically modifies crops often infect monarch butterflies and other insect species.2. viruses could combine with crops.

It is 4.92 e-4 sorry if i am wrong