<span>the intellectual and practical activity encompassing the systematic study of the structure and behavior of the physical and natural world through observation and experiment.
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All plants have a cell wall, all mammals have a cell membrane. a cell membrane is semi-permeable it allows mammal cells to absorb needed nutrients, oxygen and deposit waste into the blood stream where it is excreted through urine and feces. a plant cells nutrients are absorbed through the root system and leaves, waste is excreted in the form of oxygen through the plant itself.
A panther because it eats the primary consumer which would be the deer.
an oak tree is the producer (bottom of the food chain)
the deer is the primary consumer because it eats grass which would also be a producer
and the hawk would be the top predator because it eats a snake which would eat a mouse which would feed on a producer :)