Question

1. label the boxes to represent the gasses that are exchanged between photosynthesis and respiration. hint: think about what gas you need to survive

1. what is a possible negative effect of deforestation (cutting down forests)?

1. in your own words describe how plants and animals are dependent on each other. (besides plants being food for animals)

based on the two models and what you have learned, draw your own model to represent the processes of photosynthesis and respiration. remember good models should include arrows, labels, and/or symbols your model must be your own and not the same as the two provided or your classmates

Explanation:

Question 1

Photosynthesis uses carbon dioxide ($\ce{CO_2}$) and produces oxygen ($\ce{O_2}$). Respiration (by animals and plants) uses oxygen and produces carbon dioxide. So the top box (from respiration to photosynthesis) should be $\ce{CO_2}$ (since respiration releases $\ce{CO_2}$ which plants use in photosynthesis), and the bottom box (from photosynthesis to respiration) should be $\ce{O_2}$ (since photosynthesis produces $\ce{O_2}$ which animals/respiring organisms use).

Deforestation means fewer trees. Trees take in $\ce{CO_2}$ (a greenhouse gas) during photosynthesis. With fewer trees, there's more $\ce{CO_2}$ in the atmosphere, leading to increased global warming (climate change). Also, trees provide habitats; cutting them down reduces biodiversity as animals lose homes. Another effect: soil erosion, since tree roots hold soil, and without them, soil is washed away in rain.

Plants produce oxygen via photosynthesis, which animals need for respiration to get energy. Animals produce carbon dioxide via respiration, which plants need for photosynthesis to make food (glucose). So they depend on each other for gas exchange: plants give $\ce{O_2}$, animals give $\ce{CO_2}$, enabling both to perform their energy - producing/ food - making processes.

Answer:

Top box: Carbon Dioxide ($\ce{CO_2}$); Bottom box: Oxygen ($\ce{O_2}$)

Question 2