Waterweed grows near the surface of the water in lakes and ponds. it often grows in dense clumps. it has been observed that the chloroplasts in this plant move around inside the cell. how might this be an advantage and a disadvantage to the plant?

This might be an advantage because the Chloroplast can orient themselves so as to obtain maximum exposure to sunlight for the process of photosynthesis. It can also be a disadvantage because useful energy would be required to relocate the chloroplasts which could have been used elsewhere. 

Explanation; 
Chloroplasts are organelles where the process of photosynthesis, the process in which green plants make their own food, takes place. For maximum photosynthesis to take place the chloroplasts require maximum exposure to sunlight, therefore, the chloroplasts in the waterweed are able to achieve this, since they are moving around the cell, which is advantageous to the plant. However, this movement would cause unequal distribution of light as not all cells will be exposed to maximum sunlight and again the movement of the chloroplasts within the cell requires energy that would have otherwise been used by the cell for other activities. 

answer: carbon 14 can only be used to determine the age of the organisms that were once living, and igneous rocks are non living.

explanation:

carbon 14 dating is used to determine the age of the sample by estimating the amount of carbon 14 present in the sample and then comparing it with a reference standard.carbon 14 is a isotope of carbon which is radioactive and unstable. carbon 14 is assimilated by all plants and animals throughout their life from carbon dioxide. however, one the organisms die they stop this assimilation and the carbon 14 content starts to decrease.by knowing how much of carbon 14 is left in an organism after his death, one can estimate the age of the organism. the materials whose age can be estimated by carbon 14 method are the organic compounds. however, some inorganic compounds such as aragonite   shell can also be dated.however, if we consider the igneous rocks it is a non living component which never accumulated carbon 14 in it and thus, we cannot use carbon 14 dating method to estimate its age.