Which of the following describes the most important difference between invertebrates and vertebrates?

What were the main components of earth’s earliest atmosphere? oxygen and ammonia hydrogen and helium oxygen and nitrogen hydrogen and nitrogen

At the age of 6 months, caleb was diagnosed with tay-sachs disease. as his primary care physician, what would you tell his parents about this disease?

Describe how viruses and bacteria can be used as biological weapons. what are some of the potential threats and potential benefits? do you agree with the use of viruses and bacteria as biological weapons? why or why not?