What am I?i have no cell wall, if it weren't for me my organism would not be able to transport oxygen around their body

Identify the various levels of atmosphere. troposphere mesosphere exosphere stratosphere thermosphere

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.

Sexual reproduction in the parent cell will result in offspring with a) identical genetic information. b) half the genetic information. c) double the genetic information. d) four times the genetic information.