1. Which of these can be found in RNA but not DNA? ribose sugar
helical structure
adenine
phosphate group

Explain what a zygote is. use the terms egg cell, sperm cell, and fertilization in your explanation.

Read this summary of a scientific theory: "cells are the most basic structural and functional units of life. all living organisms are made up of one or more cells. all cells that are alive in the world today came from pre-existing cells." which of the following would require this theory to be modified? -a.) a survey finds that a majority of people believe viruses carry out the basic processes of life. -b.) a prominent scientist says she feels strongly that one day the theory will be challenged by life on other planets. -c.) the dna of unicellular and multi-cellular organisms is shown to have many fundamental similarities. -d.) scientific observations show that microscopic organisms living in the deep ocean are not made up of cells.

Kate is studying the transformation from unicellular to multicellular organisms. which metaphor is the most appropriate to apply to the map of the timeline.