O 1943
1944
1945
1948
1947
1946
1949
1950
te is the
d and
rowth
ment
ear,
гу
popu-
ni-
Figure 2.6 Calculate the changes in
the rat population between 1946 and
1947, 1947 and 1948, 1948 and
1949, and 1949 and 1950. What might
account for these changes?

Explain why biological control methods are generally environmentally superior to chemical pest control methods.

Natural selection changes allele frequencies because some survive and reproduce more successfully than others.

The picture below shows two galaxies. spiral galaxy and elliptical galaxy which of these statements best describes a similarity between the two galaxies? (2 points) both have elongated centers. both have centers shaped like bars. both change their shape from time to time. both are held together by gravitational forces.