Amineral
a.
has a chemical formula.
c.
has a characteristic internal structure.
b.
occurs naturally.
d.
all of the above.

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

In "the pig," what is the main effect that the piglet initially has on kibuka?

When does a spring tide occur? question 9 options: they occur when the sun, moon, and earth are aligned. in spite of their name, these tides occur twice a year in the spring and fall. they occur on the date of the vernal equinox each year, no matter what stage the moon is in. this is why they are called spring tides. they occur when the sun, moon, and earth are at 45-degree angles from each other. this happens once every spring. they occur when the sun, moon, and earth are aligned. in spite of their name, these tides occur all year long.