Silicon is the second most abundant element in the Earth´s crust and makes up around 27% of it.
Precipitation and temperature
ANSWER
The correct answer is A
EXPLANATION
Plants manufacture their on food by the process of photosynthesis. During this process, plants trap radiant energy from the sun by the help of chlorophyll in the leaves.
Radiant energy with other raw materials such as water, carbon dioxide and mineral salts is converted to food (in the form of starch) which contains chemical energy.
Answer: d. have the silicon-oxygen tetrahedron as their structural unit.
Explanation:
Silicates are anions that have both Oxygen and Silicon as the basis of their structure. These two form a tetrahedron type structure that enable them to be useful for a whole lot of things.
Silicates are very abundant on Earth as they comprise around 95% of the Earth's crust as well as the upper mantle which explains why they are mostly found in igneous rocks.
The variable is what changes during an experiment. Hopefully this helped! :)