A flask containing photosynthetic green algae and a control flask containing water with no algae are both placed under a bank of lights, which are set to cycle between 12 hours of light and 12 hours of dark. The dissolved oxygen concentrations in both flasks are monitored. Predict what the relative dissolved oxygen concentrations will be in the flask with algae compared to the control flask. The dissolved oxygen in the flask with algae will always be higher. The dissolved oxygen in the flask with algae will always be lower. The dissolved oxygen in the flask with algae will be higher in the light, but the same in the dark. The dissolved oxygen in the flask with algae will be higher in the light, but lower in the dark. The dissolved oxygen in the flask with algae will not be different from the control flask at any time.

The dissolved oxygen in the flask with algae will be higher in the light, but lower in the dark.

Explanation:

Photosynthetic algae as the name implies are capable of carrying out photosynthesis strictly in the presence of light. However, one major product of the photosynthetic process is OXYGEN GAS.

According to this question, an experiment consisting of two flasks is performed. One flask contains photosynthetic green algae and the other flask is a control flask containing water with no algae. Both flasks are placed under an intermittent cycle of 12 hours light and 12 hours dark.

This means that the flask with algae will photosynthesize in exposure to light and produce oxygen gas while it uses up the oxygen in the dark via cellular respiration. Therefore, in a nutshell, the dissolved oxygen in the flask with algae will be higher in the light due to photosynthesis, but lower in the dark due to cellular respiration.

"1. it should be, it has been for about 20 years, and it's really not much different in the end than breeding animals to have particular traits. there are always concerns about genetically engineered animals/plants affecting the environment in unexpected negative ways, but i can't think of an example where the fears didn't turn out to be baseless.  

first, as you point out, it would be a great advance in pharmacology, to be able to tailor drugs and their doses to me. the pros involve better medical treatment. the cons involve privacy issues like insurance companies denying coverage to people with genetic risk factors. looking at dna markers wouldn't affect the frequency of genetic diseases, but it would allow detection of them earlier. and ok, actually i suppose that if people used this information to avoid having children with genetic diseases, some might decrease in frequency."