Fran finds a dark-colored rock that she identifies as basalt. which property gives the rock its dark color? its shape its banding its grain size its mineral content

The right option is; its mineral content

Mineral content is the property of the rock that gives the rock its dark color.  

Minerals are the building blocks of rock and rocks mainly derive their colors from them. Most rocks contain various types of minerals that are joined together while few rocks contain just a type of mineral. Rocks that their mineral constituent is pyroxenes, olivines or amphiboles are usually dark in color while rocks that have much of feldspar and quartz are usually light in color.

the two answers are a, the population of birds with large beaks will increase on the island, and c, the trait for large beaks will be passed on to future generations through natural selection. the reason for that is because if the birds that have beaks developed for eating small seeds lose all of their food, they will go hungry and eventually starve because they physically cannot eat the large seeds, therefore making the population of large beaked birds higher. also, if the trait of large beaks are dominant on the island over small beaks, then over time the large beaked birds will reproduce more and more, while the smaller beaked birds will reproduce less and less because they can't survive with the food provided. that leads to the trait of small beaks disappearing and the trait of large beaks taking over the island.