Which scientists discovery enabled other scientists to develop a better understanding of cells

Which of the following is not a way in which a vascular plant's xylem and phloem are similar?

List five ways we are indebted to phytoplankton

After dinner with his brother, charles darwin looked through a book by thomas robert malthus, who believed that humanity, if unchecked, could double its population size in 25 years . why then , wasn't the earth overrun with humans at this point ? how does this relate to the stoning of the darwin's carriage?