Q1. Evaluate the problems that animals face in locating source of a visual signal with the problems they face in locating the source of an acoustic signal. What aspects of these problems are inherent in physics of light and sound, and what aspects are consequences of the evolutionary history of animals you are considering?"
Q2. According to some theories, Earth's sun is approximately 5 billion years old. After about 10 billion years, this type of star runs out of fuel. The hydrogen in the core becomes depleted and cannot be used to form helium. The graphs below exemplify the chemical changes that occur inside a star at specific times.
Using information provided, what is the hydrogen/helium content inside a star that is the approximate age of our sun?