A scientist observes that when she opens the back door of her house to let her cat out, the songs of a certain species of bird abruptly change. She wants to follow up on her observations with an informal experiment. Which of the following is the best hypothesis for explaining the birds’ song changes?A. The bird species switches from song to warning call whenever it sees a potential predator. B. The bird species has a variety of songs that it sings, regardless o what is happening in its environment. C. The scientist is mistaken and the songs do not change. D. The bird species switches from song to warning call whenever it sees a potential predator.

A and D (you've written them as the same thing?)

Explanation:

how do heroes resolve conflicts in beowulf?

question 15 options:

they sue each other in court

they get a mediator

the seek counseling

they get even or take revenge

explanation:

the correct answer is - d. china has a large and growing population.

the fact that china has a large (the biggest) population, and it is still growing, doesn't hinder the agriculture production in the country. in fact, it can for increased production in the agriculture, since there's more labor force, as well the sheer mass of people produces lots of scientists that come up with new inventions as to how to improve this sector. nice example is the inner mongolia region in china, in general dominated by the gobi desert, but few scientist came up with a nice idea as to how to make the region productive by using plants that are very resistant to droughts, so lots of people have been employed, and the region is becoming greener and greener each year, and the production of food in this region is also increasing.