When the earth first developed there was no oxygen. the first living organism, cyanobacterica, added oxygen to the earth. explain why this is was important and what it to create on the earth in order to protect living organisms

As an asteroid comes close to earth, it's name will change to? apex

Imagine you are a student in alfred hershey and martha chase's lab in the late 1940's. you are given five test tubes with the e. coli bacteria that were infected with t2 bacteriophage that have been labeled with 32p or 35s. unfortunately, you forgot to label the tubes and are now uncertain which were 32p labeled and which were 35s labeled. you place the contents of each tube in a blender and pulse it for a few seconds to shear off the protein coats from the bacterial outer membranes. you then centrifuge the contents to seperate the protein coats and the bacterial cells. you then check for radioactivity and obtain the results shown below. which tubes contained e. coli infected with the phage labeled with 32p? select all tubes that apply.

These are groups of reproducing populations that are insulated from other groups