a) Evolution is a term that means
species becoming extinct.
the gradual development of species.

b) The Earth is
about five million years old.
about five billion years old.

c) In chemical evolution,
new molecules evolved.
new species evolved.

d) A fossil is
a petrified remnant of an ancient organism.
an extinct species.

e) A vestige is
for example, a human structure that is no longer of significant importance, such as the caudal vertebrae.
an organ that remains small if not used every day..

f) Natural selection is a phenomenon
where evolution results in the emergence of new species.
where only the most eligible individuals produce offspring, or at least produce more offspring than others.

g) According to the theory of evolution,
all modern organisms have developed from organisms that lived before them.
all species have always existed on planet Earth.

h) The development of animals has followed the following pattern:
reptile → bird→ fish
fish→ reptile → bird