Why is photosynthesis vital for life?

a.

photosynthesis maintain atmospheric levels of oxygen and carbon dioxide.

b.

photosynthesis is a direct means of energy production for many organisms.

c.

photosynthesis is an indirect means of energy production for many organisms.

d.

all of the above

Which of these is true of the cytoplasm of an unfertilized egg? a. it is an unevenly distributed mixture of mrna, proteins, organelles, and other substances. b. it does not contain substances that are important in directing development. c. these substances are supplied by the sperm. d. it does not contain substances that are important in directing development. e. development is directed solely by the surrounding cells. f. it is a homogeneous mixture of mrna, proteins, organelles, and other substances. g. it does not contain substances that are important in directing development. h. these substances are produced by the dna of the fertilized zygote.