A star’s life expectancy depends on its mass. Generally, the more massive the star, the faster it burns up its fuel supply, and the shorter its life. The most massive stars can burn out and explode in a supernova after only a few million years of fusion. A star with a mass like the Sun, on the other hand, can continue fusing hydrogen for about 10 billion years. And if the star is very small, with a mass only a tenth that of the Sun, it can keep fusing hydrogen for up to a trillion years, longer than the current age of the universe.
From what I can tell, The answer is either A or B. Mammals have what is called an Endoskeleton, which means that their skeletons are inside their bodies. A way to remember this is Exo- is similar to exit and when you exit something then you are going outside. Endo- sounds like into, which can relate to being on the inside. Insects have Exoskeletons, which are made from Chitin. Now Agonists are also called Prime Mover muscles, which means they are practically the same thing.
Hydrogen ion, or H-, creates water when combined with a hydroxide ion, OH+.
The 'formula' for water is H20, two hydrogens and an oxygen.
I hope that I helped but if this still makes no sense, or if I haven't explained it as well, then please don't hesitate to ask further questions. Thank you.
The pupils will constrict (or get smaller) to let less light in.
