What type of organism provides the base of a food web

The phylogenetic tree illustrates the relationship between humans and our closest living relatives. the tree was based on biochemical comparisons, including dna and amino acid sequences. according to the biomolecular data, we could infer that

There are fewer than 100 naturally occurring elements in the universe, but there are millions of different unified substances. explain how this can be true.

18. over time, how do sand dunes tend to migrate? a. perpendicular to the movement of the wind b. in the same direction as the wind blows c. toward the wind d. in random directions