Chloroplasts are only found in plant cells because it is the organelle that makes photosynthesis possible and it makes food for the plant cells as in it makes its own food and animal cells dont need them because animals eat other animals for that food
        
             
        
        
        
<span>A. abiotic component</span>
An ecosystem involves both the biological (plants, animals, human beings) and non-biological (land, water, soil, and atmosphere) community which interacts as a system. More importantly, the living things are very dependent on the abiotic community since it cannot survive by itself. Every animal, plant and human needs the primary physiological needs of water, food and shelter provided by the abiotic system.   
        
                    
             
        
        
        
Answer:
Integrin molecules serve as stable, permanent anchors that anchor a cell to the extracellular matrix.
Explanation:
Integrins are transmembrane protein receptors that attach the cell cytoskeleton to the extracellular matrix (ECM) in animal cells. These glycoproteins (integrins) are highly dynamic heterodimeric molecules that anchor cells in their position and transduce signals into and out of cells. Integrin-ligand binding activates signaling pathways that are involved in fundamental cellular functions including, among others, organization of the cell cytoskeleton, cell migration, regulation of the cell cycle, etc.
 
        
             
        
        
        
Parasitism
Parasitism can be defined
as a relationship between species in which one organism (parasite) lives on or
in another organism which is the host, causing it some harm without immediately
killing it. Thus, parasitism is a kinds of close, symbiosis and persistent
biological interactions.