Why is astronomy considered an observational science? It is hard to do experiments in astronomy.

Scientists do not have a sample of other stars or galaxies that they can put in a bottle.

Astronomers don't like telescopes.

It is impossible to do theoretical science in astronomy.

Plz fast biotechnology is a growing field of applied biology. many crops such as corn have been engineered to be resistant to herbicides. therefore farmers can spray these chemicals to kill weeds growing near the crop without worries of killing the crop itself how does this type of biotechnology work? a. by changing the genetic make up of the crops. b. by causing the crops to kill the weeds. c. by changing the type of crops used. d. by changing the location of the crops.

Which would be the most useful source of evidence to support mcneill's contention?

Crossing over and independent assortment are important activities that occur during meiosis. what is the significance of these activities