Many organisms live in and on the human body. state which type of symbiotic relationship exist between human host and the following types of micro organisms
a. plasmodium which causes malaria
b. bacteria in the gut which supply the body with vitamin k

Which flexible structure that supports the nerve cord and led to the backbone

How can a geological time scale best be reconstructed? a) comparing vestigial structures in living species b) comparing homologous structures in living species c) examining homologous structures in fossil remains d) examining the written records of scientists from past cultures

If a strand of dna has 35% thymine. what is the percentage of cytosine, adenine, guanine?