Which characteristic is shared by extrusions, intrusions, and faults?

all are cracks.
all are igneous rocks.
all cause gaps in the geologic record.
all are younger than surrounding rocks.

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

What sentence best supports the statement that hormones are involved in the regulation of homeostasis? a. the hormone erythropoeitin increases the production of red blood cells when oxygen levels are low. b. the hormone oxytocin promotes labor contractions of the uterus during childbirth. c. the hormone melatonin induces sleep and its production is slowed by exposure to light. d. the hormone cortisol suppresses the immune system and is produced when the body is under stress.

Explain why the plants cortex would serve as the best food source for animals