The role of grass is the primary producer because it is the beginning of almost every food chain.
The unknown type of corn had to be
yellow.
There were offspring that were red and yellow.
The red corn only has recessive alleles (r and r) so, the yellow alleles( R) didn't came from this type. They came from a yellow type corn.
And since the offspring were NOT all yellow (the dominant color) we know that the yellow corn was
heterozygous for the color trait (Rr).
50% red (rr)
50% yellow (Rr)
humans cannot impact one of Earth's systems without impacting the others because Earth's systems are interconnected. They interact with each other, moving matter from one system to the other. Changes to the atmosphere brought about by human activity eventually lead to changes in the biosphere and hydrosphere.
Cyanobacteria helped produce O2. Because it helped releasing O2 into the atmosphere, today we see different animals because Cyanobacteria helped reduce the poor oxygen in the atmosphere.