The activation energy of a reaction going on its own is 20 kj. if the reaction was treated with a catalyst, which would most likely represent the amount of energy needed to start a reaction?
15 kj
20 kj
25 kj
30 kj

Arafura file snakes are large, aquatic, non-venomous snakes found in the flood-plains of australian rivers. they feed only on fish found in the rivers. it has been observed that heavy rainfall in the wet season in one year leads to prolonged inundation of the floodplains lasting a year or longer. it has also been observed that these snakes remain in good physical condition after a flood. explain how the file snake population in a region is likely to be affected by the prolonged inundation of a flood-plain.

One statements is an example of a scientific observation. another statement is an example of a scientific explanation. identify the correct statement for each category to illustrate how scientific explanations are inferred from scientific observations.

Explain how ancient whale fossils found in eqypt are believed to support the theory of evolution.