Which plants first developed a circulatory system?
a.
mosses
c.
ferns
b.
worts
d.
horsetails

The green colored pigment in chloroplasts is? a. nitrogen b. chlorophyll c. chlorophorm d. chlorofloromethane

The large increase in atmospheric carbon dioxide in the last 50 years most likely comes from a. an increase in cellular respiration b. increased decomposition by bacteria c. an increase in the burning of fossil fuels d. an increase in photosynthesis

The earths core is made up mainly of what 2 substances? 2. like an egg, earth has a core, a layer surrounding the core, and a thin, hard outer layer. which layers of the earth match the layers of an egg?