Answer:
element Y and Z
Explanation:
Having on valence electron indicates that these elements are on the same column/group of the periodic table. Both these elements will bond with a -1 charge.
 
        
                    
             
        
        
        
Phosphorus is usually a limiting factor or element.
<h3>Is phosphorus a limiting element or factor?</h3>
Phosphorus is usually considered a limiting factor or nutrient in aquatic ecosystems, meaning that the available quantity of this nutrient controls the pace at which algae and aquatic plants are produced.
In other words, phosphorus is a limiting nutrient for aquatic organisms. Its supply is usually small compared to available aquatic organisms.
Thus, Phosphorus is usually a limiting factor or element.
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Contractile proteins<span> generate force for muscle contraction. The two </span>contractile proteins<span> in myofibrils are actin (part of the thin filament) and myosin (part of the thick filament)</span>
        
                    
             
        
        
        
Answer:
a) prophage
Explanation: triggered to become active with exposure to radiation, heat, a particular chemical, or some other factor
 
        
             
        
        
        
Land plants are evolved from green algae.
Green algae called charophytes are coolest relatives of land plants. 
It is believed that land plants are the most closely related to green algae, more specifically, a group of green algae referred to as charophyceans. Not only do both land plants and green algae produce chlorophyll a and b, but other evidence suggests that there is a relationship as well.
4 key traits that appear in nearly all land plants but are absent in the charophytes.
 -Diploid embryos
- The ability to photosynthesize
-Apical meristem
-Walled spores produced in sporangia.
- Multicellular haploid and diploid generations
-Multicellular gametangia
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