Mollusks are marine animals that prey mainly on sponges. These sponges provide some nutrients, but not very many lipids (fars). While most mollusks live in tidal pocls, some mollusks live in the cleep ocean, near hydrothermal verys Sponges cannot,survive at these depths. However, scientists have observed many chemosynthetic bacteria living near these vents, Chemosynthetic bacteria change chemicals in the water into molecuies such as lipids that other organisms can use as food. Biologists claim that the bacteria and mollusks have a mutualistic relationship. The biologists think that the chemosynthetic basteria find shelter on the skin of mollusks. In return, the mollusks gain high levels of lipids from the chemosynthetic baxteria. Which two investigations would help the biologists investigate their claim of a mutualistic relationship? A. Keep track of the mollusks living near the vent. Test samples of mollusks for high levels of lipids. B. Put mallusks and sponges in a lab environment that is like the deep ocean. Count how many sponges the mollusks eat. C. Raise mollusks in freshwater ponds. Add chemosynthetic bacteria to the freshwater and check for high levels of lipids in the water. D. Move the mollusks away from the vents so that they cannot absorb chemicals from the vents, check If the mollusks repreduce. E. Make a lab environment that is like the deep ocean, hydrothermal vent habitat, but without mellusks Compare the size of the bacteria population over time in the lab and real environment.

## Step 1<br />The problem is about the mutualistic relationship between mollusks and chemosynthetic bacteria. The mutualistic relationship is a type of symbiotic relationship where both organisms benefit from each other. In this case, the mollusks provide shelter for the bacteria, and the bacteria provide lipids for the mollusks.<br /><br />## Step 2<br />The biologists want to investigate this relationship further. They need to design experiments that can help them understand this relationship better.<br /><br />## Step 3<br />Looking at the options, we need to identify which two investigations would help the biologists investigate their claim of a mutualistic relationship.<br /><br />## Step 4<br />Option A suggests keeping track of the mollusks living near the vent and testing samples of mollusks for high levels of lipids. This would help the biologists understand if the mollusks are indeed gaining high levels of lipids from the bacteria.<br /><br />## Step 5<br />Option B suggests putting mollusks and sponges in a lab environment that is like the deep ocean and counting how many sponges the mollusks eat. This would help the biologists understand if the mollusks are indeed eating more sponges than usual, which could indicate a mutualistic relationship.<br /><br />## Step 6<br />Option C suggests raising mollusks in freshwater ponds and adding chemosynthetic bacteria to the freshwater and checking for high levels of lipids in the water. This would not be a good investigation because the conditions are not the same as the deep ocean.<br /><br />## Step 7<br />Option D suggests moving the mollusks away from the vents so that they cannot absorb chemicals from the vents and checking if the mollusks reproduce. This would not be a good investigation because it does not directly test the mutualistic relationship between the mollusks and the bacteria.<br /><br />## Step 8<br />Option E suggests making a lab environment that is like the deep ocean, hydrothermal vent habitat, but without mollusks and comparing the size of the bacteria. This would not be a good investigation because it does not directly test the mutualistic relationship between the mollusks and the bacteria.