The greenhouse effect occurs when rays enter our atmosphere and are reflected from the ground up. They get changed during their voyage through our atmosphere and they change in such a way that they can't leave the atmosphere anymore. Then they stay inside and heat up the planet which causes thing like global warming. That's what the greenhouse effect is.
A. occurs mostly in males. Females may exhibit symptoms but rarely. Female carriers are asymptomatic (not affected). Characteristic cannot be transmitted male to male. Affected males transmit the trait to all daughters.
Possible gamete's genotypes in both parents are: SY, sY, Sy, sy
Genotypic ratio: SSYY 1 : SSYy 2 : SsYY 2 : SsYy 4 : SSyy 1: Ssyy 2: ssYY 1: ssYy 2: ssyy 1
Phenotypic ratio: yellow, spherical 9 : yellow, dented 3: green, spherical 3 : green, dented 1
Take a look at the attachment :)
I believe they cannot start with big trees and bushes because the there is not enough nutrients in the soil, so instead pioneer species pave the way for primary succession.