Getting Started
Why didn't people know about germs or microbes before the mid-1800s?

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.

Which statement does lola need to correct, and why? a) statement 1 because spiral galaxies do not havearmsb) statement 2 because the bulges contain mostlyyoung red stars. c) statement 3 because the arms are made of mostlyyoung blue and blue-white stars. d) statement 4 because spirals galaxies contain littleto no dust.(c)

Select the correct answer from each drop-down menu the images show fossils of a modern bird and two extinct organisms (a tyrannosaurus rex and an archaeopteryx). based on the structure of the three organisms, it can be concluded that the archaeopteryx and bird have wings, while dinosaurs have limhe se it can be concluded that