How is the plasma membrane of a cell organized?
question 15 options:

one layer of phospholipids, through which proteins freely move

one layer of phospholipids, which are laid out end-to-end, with a hydrophobic tail touching a hydrophilic head

two layers of phospholipids, each of which has its hydrophilic side turned inward

two layers of phospholipids, with their polar hydrophilic heads facing away from each other

The correct option is D. two layers of phospholipids, with their polar hydrophilic heads facing away from each other

Explanation:

The cell membrane is made up of two layers of phospholipids. The structure of phospholipids comprises of a hydrophobic tail which is made up of fatty acids and a hydrophilic head that is made up of phosphate. The structure of a cell membrane contains two fatty acid tails.

As the tail is hydrophobic, hence it is shielded and located inwards. The hydrophilic heads are located outwards in opposite directions.

answer( increase) their individual contractile activity;

1) a giant star is a star with a radius much larger than that of our sun (even hundreds of times bigger). they can be either blue giants or red giants: in the first case, the surface temperature is very high, higher than that of the sun, while in the second case the surface temperature can be lower than that of the sun. the same applies to the mass: blue giants are very massive stars, burning quickly their nuclear fuel, while red giants can have small masses (a little bit bigger than that of our sun).

2) we can find giant stars in the upper part of the hr diagram, blue giants will be on the upper left corner since they have high luminosity and high temperature, while red giants will be on the upper right corner, having high luminosity but low temperature.