State two reasons why pH maintenace is important in biological systems.

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.

Which short-term environmental changes would a very small asteroid or comet impact on earth most likely cause? check all that apply. flooding extinction craters on surface changes in weather patterns death of organisms and populations

What happens when two nitrogen atoms share electrons