Answer:
Leaves lose the most chloroplasts at the end of summer.
Insulin released to prevent the surge of sugar in bloodstream when glucose increases.
The right answer is Lichen.
In ecology, a pioneer species is one of the first forms of life that colonize or recolonize a given ecological area.
Lichens are composite organisms resulting from a symbiosis between at least one heterotrophic fungus called mycobionte, representing 90% of all, and microscopic cells with chlorophyll (green algae or cyanobacteria autotrophic for carbon) called "photobionts" .
I don't know how specific you need to get for this question. The basic answer would be the mitochondria as it is where the Krebs Cycle, the Electron Transport Chain, and Chemiosmosis (also referred to as oxidative phosphorylation) all occur. Chemiosmosis is where the majority of ATP is produced during cellular respiration, and it primarily occurs in the matrix of the mitochondria as protons move down the gradient through ATP Synthetase channels.