Answer:
A. donation of excited electrons by chlorophyll a to a primary electron acceptor
Explanation:
Photosystems are structures located at the thylakoid membrane that act to harvest energy light in order to convert it into chemical energy. Each photosystem is composed of a light-harvesting complex and a core complex, which in turn is composed of a reaction center. The photosynthetic reaction centers are multi-protein complexes that use light energy to catalyze the electron transfer across the chloroplast thylakoid membrane against a thermodynamic gradient. Moreover, antenna pigments are pigments that capture the energy from photons in order to transfer energy to other pigments in the photosystem (e.g., chlorophyll B and carotenes are antenna pigments, whereas chlorophyll A is the core pigment). Light energy absorbed by antenna pigments in the photosystems is transferred to the reaction center chlorophyll A molecules, thereby exiting electrons in the reaction center. A reaction center consists of two chlorophyll A molecules, which donate electrons to the primary electron acceptor.
Sperm cells are produced in the Epididymis, to get to the urethra they must travel through the Vas deferens.
a. parsimony; simplest; fewest
When selecting among multiple possible phylogenetic trees that fit our data, we commonly use the principle of <u>parsimony</u>, which means we choose the <u>simplest</u> possible hypothesis. In phylogenetic analysis, that means selecting the tree that represents the <u>fewest</u> evolutionary changes or mutations.
Explanation:
Phylogeny describes the evolutionary history of on organism or group of organisms.
A phylogenetic tree structure is used to describe the relationship between various organisms which have originated from common ancestors.
The Principle of Parsimony is best applied while constructing phylogenetic tree.
This principle emphasizes on simple observations on a phylogeny which requires only few changes or variations which explain for the difference between the phylogenic sequences.
This tree structure will only have few specific genetic variations or mutations or evolutionary changes which took place through new appearance of a trait or disappearance of an existing trait.
Okay. The destruction of tundra vegetation will not really freeze the soil or deepen the active zone much. Therefore, A and C are eliminated. The destruction of the vegetation can actually melt permafrost, which contributes to global warming. The answer is D.
