I believe the polysaccharide that provides rigidity and strength in plants would be cellulose. As this is one of the essential components found in the cell wall of plant cells.
Answer:
The crust
Explanation:
The solid, outer layer is called the crust.
Answer:
oxygen
Explanation:
A limiting factor is any condition whose decrease, increase, absence or presence is able to limit/stop population growth. Examples of limiting factors include abiotic conditions (e.g., temperature, water, oxygen, CO2, etc) or biotic conditions (e.g., food, mate, etc). There are many aquatic species that require high levels of oxygen (e.g., fish), thus being it a limiting factor for these species.
