Its because a long spine cacti can reproduce more because it has more survival capacity than the short spine cacti and because of this reason the short spine cacti cannot protect it self because it has a shorter spine that could protect itself from danger.
Nucleic acids store hereditary information. Think about DNA! DNA stands for dioxiriboNUCLEIC ACID. Your DNA determines everything about you’
Cell membrane is a semipermable, which means that certain molecules will be able to pass through the membrane. It is contains phospholipids. But for smaller molecules such as CO2 and Water, it can pass through the membrane through simple diffusion. Cell membrane controls the movement of the materials into and out of the cell.
An endoskeleton of calcified cartilage