Answer:
b. a semi-permeable double layer of phospholipids that have hydrophilic heads and hydrophobic tails
Explanation:
B is correct as the cell membrane is selectively semi-permeable. It is selectively semi-permeable because this quality allows it to control what can and can't enter the cell, and how it does so.
The cell membrane also has a phospholipid bi-layer comprised of a double layer of phospholipids which have hydrophilic head and hydrophobic tails. This is because the heads are made of phosphate and are polar and are therefore attracted to water (hydrophilic), while the tails are made of lipids (i.e. fats, oils) which do not mix with water and are therefore hydrophobic.
The properties of each phospholipid is also why they form the double layer structure, the hydrophilic heads naturally face outwards into the water and protect the hydrophobic tails on the inside.
Hope this helped!
The three mechanisms which regulate the heart are endocrine, cardiovascular and Sinoatrial nodes.
The endocrine system consists of the glands and hormones of the human body. The cardiovascular system is the organ system which is responsible for the circulation of the blood around the body and the oxygenation of the body's tissues. The sinoatrial node (SA node) generates the electrical impulses and is considered the natural pacemaker of the heart.
It sends waves from satlights to ur inntina
Answer:
Fusion of embryonic myoblasts, each having its own nucleus to many other myoblasts to form the multinucleated skeletal muscle fibers.
Explanation:
The multiple nuclei in skeletal muscle cells are as a result of fusion of embryonic myoblasts, each having its own nucleus to many other myoblasts to form the multinucleated skeletal muscle fibers. This gives rise to multiple copies of genes, allowing production of the large amounts of proteins and enzymes and ATPs needed for muscle contraction.
There was two of the same question, but here is the answer again with a little more depth.
D - spine alignment and foot size.
It was only the late Australopiths that had an S-shaped spine. This allowed for them to be bipedal, that is, the ability to walk on two legs as we do. This is because the S-shaped spine allowed them to balance when they were standing. The late Australopiths also have shorter and less flexible toes. These smaller, but sturdier feet made pushing off the ground much easier - aiding in their bipedalism.
