Helppp pls ASAP I need it now

How many trophic levels are there in the following food chain? phytoplankton - shrimp - perch - pike - osprey

Place the steps tor the formation of the enzyme pepsinogen in correct order

An organ system consists of a group of organs that performs specific functions necessary for the survival of an organism. humans have eleven different organ systems: integumentary, skeletal, muscular, nervous, endocrine, circulatory, lymphatic, respiratory, digestive, urinary, and reproductive. discuss the function of neurons, the brain and the spinal cord within the human nervous system while explaining the interrelationship of each organ.