Over the last few weeks we have learned a lot about humans, and impact on their environment. Some say that we have helped make the earth a better place while others say we are doing more harm than good. Take a stance. Do you believe humans have helped improve the earth or caused more harm than good. Why or why not?

the second type of galaxy is called a barred spiral, which has a thing called a bar straddling the nucleus

the correct answer is: b. pantala flavescens, because these organisms would have a high level of genetic variation due to sexual reproduction.  

because involves two organisms (parents) whose genetic material combines, sexual reproduction leads to genetic variation in new generations of offspring. the offspring is an unique organism, with new genome, more protected with the higher ability to adapted. this process is fundamental to evolution.