Answer:
Closed the first one
Explanation:
In amphibians, reptiles, birds, and mammals, blood flow is directed in two circuits: one through the lungs and back to the heart, which is called pulmonary circulation, and the other throughout the rest of the body and its organs including the brain (systemic circulation).
most mammals, have closed cardiovascular systems. The two main circulation pathways in invertebrates are the single and double circulation pathways.
The backup of sewage in the preparation area and serious pest infestations are hazards that requires closure. In which should be important to have considering their harmful substance and causes, some also include significant lack of refrigeration and lack of interruption of electrical or water service.
Answer:
A. engulfing of small photosynthetic prokaryotes by larger cell
Explanation:
The endosymbiotic theory states that some of the organelles in today's eukaryotic cells were once prokaryotic microbes. In this theory, the first eukaryotic cell was probably an amoeba-like cell that got nutrients by phagocytosis and contained a nucleus that formed when a piece of the cytoplasmic membrane pinched off around the chromosomes. Some of these amoeba-like organisms ingested prokaryotic cells that then survived within the organism and developed a symbiotic relationship.
Some Evidence for this is based on the following:
1. Chloroplasts are the same size as prokaryotic cells, divide by binary fission, and, like bacteria, have Fts proteins at their division plane.
2. The mitochondria are the same size as prokaryotic cells, divide by binary fission, and the mitochondria of some protists have Fts homologs at their division plane.
3. Mitochondria and chloroplasts have their own DNA that is circular, not linear.
4. Mitochondria and chloroplasts have their own ribosomes that have 30S and 50S subunits, not 40S and 60S.
5. Several more primitive eukaryotic microbes, such as Giardia and Trichomonas have a nuclear membrane but no mitochondria.
