And reactions are both parts of photosynthesis. a) variable; fixed b) single; and double replacement c) glycolysis; electron transport eliminate d) light-dependent; light-independent

The right option is; D) Light-dependent; light-independent

Light-dependent and light-independent reactions are both parts of photosynthesis.  

Photosynthesis is a chemical process by which plants and other photoautotrophs generate carbohydrates and oxygen from carbon dioxide, water, and light energy in chloroplasts. During the process of photosynthesis both light dependent reaction and light-independent (dark) reaction occur in the chloroplast. The light reactions depends on light to generate organic energy molecules (ATP and NADPH) which are stimulated by chlorophyll (green colored pigment) while the dark reactions is light independent. It takes place in the stroma and ATP energy is used, while the electrons that are needed to fix carbon dioxide into carbohydrates is provided by NADPH.

the law of original horizontality explains:   why rocks appear in layers. correct answer: b the law suggests that all rock layers are originally laid down (deposited) horizontally and can later be deformed.   the principle is used by geologists to make assumptions about the relative ages of sedimentary rocks.