How are cellular respiration and photosynthesis interrelated?

The concept of keystone species is controversial among ecologists because most organisms are highly interdependent. if each of the trophic levels is dependant on all others how can we say one is most important

Common symptoms of an iron-defiency anemia include muscle weakness shortness of breath and lightheadedness why does iron deficiency causes these symptoms

Aresearcher created three groups based on participants bmi: normal weight, overweight and obese. the hypothesis being tested is that the three groups differ in the mean number of artificially sweetened drinks consumed weekly. which statistical test might the researcher use, assuming a reasonably normal distribution of values.