Carbon atom is tetravalent in nature. how many hydrogen atoms can bind to one carbon atom?

What happened to rosalind franklin in 1956?

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

The tubes transporting minerals and water upward are called ?