If one population dies out, all the populations that depend on that species for food may also die out. A change in one population affects the entire community because all the populations of a community depend on each other. A population is all the members of one type of organism living in an ecosystem.
        
             
        
        
        
Answer: (A) The conclusion is valid because the independent and dependent variables in experiment were controlled.
Explanation: There are some basics requirements in order for an experiment to be valid: hypothesis, monitoring, independent and dependent variables and constants.
 
        
             
        
        
        
Invasive species can either replace an organism from the ecosystem food web or replace it.   
Explanation:
- Invasive species are non-native species which can be animals, plants, micro-organisms, fish, etc. they are very much threatening to the native species and ecosystem food web.
 - Invasive species are spread by humans mostly, it happens unintentionally when people travel and all. Even climate change could be a reason for its spread.
 - So, it becomes threatening to native species because when you introduce it into a new ecosystem, it does not have a predator or control. It grows aggressively and takes over the resources for the native species. 
 
 
        
             
        
        
        
in question number 6, the correct answer is false. this is because arrow  C is representing a combustion reaction whereby hydrocarbon or organic carbon from the fossil fuel is burnt in the presence of oxygen to produce carbon dioxide. this process is not conversion of chemical energy to mechanical energy. in this process energy will still be stored in form of chemical energy in the bonds of carbon dioxide and water produce
in the question number 7 the correct answer is true.  this is because the green plant is using energy from the such for the process of photosynthesis. photosynthesis is a process by which green plants make their own food using energy from the light. light energy is used to split the molecules of water to oxygen and hydrogen ions. oxygen is released into the atmosphere whereas hydrogen ions are used in the dark stage of photosynthesis a process referred to as carbon fixation. the end result of carbon fixation is production of organic compounds such as glucose, protein and lipids among others. these foods store energy in form of chemical energy. so arrow A represents transfer of solar energy to chemical energy 
in the question number 8, the arrows that represent the release of carbon dioxide include arrow C and arrow F. in arrow C the process occurring is referred to as combustion and it occurs when hydrocarbon in fossil fuels reaction with oxygen in the presence of heat to produce carbon dioxide and water. the arrow F represents respiration, a process by which living cells manufacture energy in form of ATP from organic food such as glucose. respiration end products include water carbon dioxide and ATP. it is essentially the reverse of photosynthesis 
in question number 9, arrow E represents cycling of carbon from living organisms to non-living organisms. this is because it is showing conversion of a carbon from the dead tree to fossil fuel. when plants and animals die and buried deep in the ground, they are slowly converted to fossil fuels which contain organic hydrocarbon compounds including petrol, kerosene and other compounds. 
in question number 10, arrow B & C show the conservation of energy and mass. when living organisms die they are converted to fossil fuels which are used in industries to produce energy required for various activities. during this process carbon dioxide is released into the atmosphere and it is used by plants in the process of photosynthesis as shown by B. this is conservation of energy and mass the number of carbon in the fossils fuel initially came from living plants and when fossil fuel is combusted it produces carbon dioxide that will be used in the process of photosynthesis and cycle continues.       
 
        
             
        
        
        
Answer:
B. Open Stomata
C. Transpiration 
Explanation:
Even though plants take up a lot of water from their roots, they lose about 95% of it to the atmosphere in the process known as Transpiration.
Transpiration is done for several reasons: it cools the plant down, it enables plants to access the nutrients in the water as the water moves along the plant and it enables gaseous exchange. 
The gaseous exchange happens because carbon dioxide comes in from the same holes on the leaf that the water leaves through to the atmosphere, the open stomata.