What is the autotroph and herotroph for photosynthesis

25) a student takes four samples of a white crystalline solid and places each in a well plate. on top of each sample, she carefully places 20 drops of clear mystery liquids a, b, c and d. her results for each well are: liquid a: the solid dissolves quickly. liquid b: the solid appears unchanged. liquid c: a brownish colored liquid is produced. liquid d: fizzing occurs and the well becomes warmer. in which well does a physical change occur?

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

The terrestrial planets are characterized by having a a.) silicate core b.) iron-rich silicate core c.) iron-rich metallic core d.) none of these