What is the total length of alimentary canal?​

How can scientists test their ideas about the origin of the universe if they can't physically interact with or study?

Which statement correctly describes a way that mutations increase the likelihood that a species will survive in a changing environment

Ineed to get this test done which of the following statements is correct in hour our immune system responds to a potential pathogen? a.) the skin will be the first line of defense, and then the many phagocytes in the bloodstream will attempt to consume the possible pathogen. b.) b cells will start reading the antigen code immediately and call t cells to assist in destroying the pathogen. c.) the adapted immune system will call on the innate immune system to destroy the pathogen. d.) the t-cells in the adapted immune systems are the first to recognize the pathogen