If a large animal such as a human being had a thin light exoskeleton, there would be several problems. Since the exoskeleton would not be able to hold its shape, it would be difficult to keep the vital organs protected and the organism would be subject to damaging levels of stress just by moving around. They are not strong enough to hold organs or hold its shape.
Answer;
The substance that can enter a cell by diffusion without having to be digested is water.
Explanation;
Diffusion involves the movement of molecules from a region of high concentration to a region of low concentration, down a concentration gradient.
Water is able to diffuse through the cell membrane without being digested since it has small molecules.
One property of cell membrane is semi-permeability; it selectively allows material to enter or leave the cell. Large molecules such as starch , fat and proteins, can not enter the cell due to their size and will need to be digested to small molecules for the to gain access to the cell.
Answer:
The correct answer is 4. The presence of a polar or charged head group attached to the phosphate.
Explanation:
Lipids have a hydrophilic head and a hydrophobic tail. This allows them to form structures where the tails are hidden on the inside, and the heads interact with the water molecules. This conformation is the best energetically and allows the lipids to interact with aqueous environments.
ultra violate radition
UV is an environmental human carcinogen. It’s the most prominent and universal cancer-causing agent in our environment. There is very strong evidence that each of the three main types of skin cancer (basal cell carcinoma, squamous cell carcinoma and melanoma) is caused by sun exposure. Research shows that as many as 90% of skin cancers are due to UV radiation.
