Answer:
a cell in a plant that is composed of a cell wall and multiple organelles, like a huge vacuole and chloroplasts that carry out photosyntheses. They are the building blocks for plants.
Explanation:
 
        
                    
             
        
        
        
Answer:
The correct answer will be option-thick bundles of fibers that allow communication between the brain’s hemispheres. 
Explanation:
Cerebral commissures are the thick fiber tract composed of white matter which connects the same cortical areas of the left and right hemispheres of the brain.
Commissural fibers include many types of fibers in which corpus callosum fibers are one of the types of fibers which act as the main Cerebral commissures.
Since these fibers connect the two hemispheres, therefore, they help in the communication between two hemispheres.
Thus, the selected option is the correct answer.
 
        
             
        
        
        
Answer:
There are several environmental factors that causes changes in the ecosystem and the population of that area such as invasive species, extreme weather, land use change, pollution and disease.
Lets take invasive species as environmental factor. Introduction of invasive species can cause a huge change in the ecosystem and affects the native population in that area. it increases the competition for food resources and decreases the survival rate of their preys.
For example: Water hyacinth (Eichhornia crassipes). It is an invasive plant species that has very bad impact of native population as well as other population, like it reduces biological diversity, oxygen loss, decreased phytoplankton productivity,  eliminate plants that animals use for nesting, and alter animal communities by blocking access to the water.
Thus invasive population can affect population by reducing biodiversity, water shortages, decreasing availability and quality of key natural resources, disturb the food chain and can cause natural calamities.
Invasive species affect the resources that native species are using and that decreases the carrying capacity of the native population as it disturbs the whole food chain.
 
        
             
        
        
        
<span>A tropism is a movement of an organism toward or away from a stimulus. A positive tropism is when the organism moves toward the stimuli. A negative tropism is when the organism moves away from the stimuli. So, your answer will be negative tropism, since the stem is growing up and out of the soil, AWAY from gravity.</span>