Dr. Blackwell caused rats to stop breathing when he lesioned their MEDULLA.
When doctor Blackwell induced a lesion in the rats' medulla, he discovered that the rats stopped breathing. He explained this observation by saying that the medulla has functional role to play in the breathing process of rats.
You know this! Let me walk you through! First, define a trophic level.
Multi cellular organisms are composed of many cells whereas unicellular organisms are composed of single cell. Multicellularity is indeed a progressive attribute of evolution where cells form tissue which forms organ and then organ system and finally an organism. Both multi cellular and unicellular organisms has advantages and disadvantages of their own. One of the main disadvantage of multi cellular organisms is that due to such a complex composition and functioning they require a large amount of energy for their maintenance and survival. Different organs and system require a huge amount of energy when it comes to comparison with unicellular organisms. A large amount of energy is also wasted in all these life processes. Though multi cellular organisms can survive in a variety of environmental conditions but then also their survival is difficult than any unicellular organism.
Homogeneous chromosoms pair up
