Answer:
The mechanisms of transport across the cell membrane are as follow: 1- simple diffusion, 2- facilitated diffusion, 3- primary active transport and 4-secondary active transport
Explanation:
The cell membrane is a selectively permeable structure capable of transporting substances by different mechanisms. Simple diffusion is a type of passive transport (i.e. does not require energy) where non-polar molecules (e.g. O2, CO2) pass across the membrane by a process that does not require energy from the cell. Facilitated diffusion is another type of passive transport where larger polar molecules (e.g., glucose and amino acids) pass across the membrane by using specific transmembrane integral proteins. On the other hand, primary active transport is a type of active transport that uses chemical energy (e.g., ATP) to move substances such as metal ions (Na+, K+, Ca2+) across the cell membrane against their concentration gradient. Finally, secondary active transport is another type of active transport where transporter proteins are used to couple the movement of ions (e.g., H+ protons) down their electrochemical gradient to the transport of another ions/solutes against their concentration/ electrochemical gradient.
Hey There!
Here is your answer:
Your answer is that a experiments should be controlled because the experiment could go out of control which could harm or hurt someone.
Also the definition of a controlled experiment is a part of the experiment that's not touched.
Ex: Water is your controlled experiment that's because our not doing anything to the water.
If you need anymore help just ask me!
Hope this helps!
Explanation:
during the embryonic stage the baby grows its organs
Nervous system. This is one of the first things that develop. It includes the formation of the baby’s brain, spinal cord, and nerves.
Heart. An S-shaped tube forms on the front of the embryo. This will become the baby’s heart. At first the heart does not beat, but soon it starts beating and pumping an early form of blood.
Face. The baby’s facial features begin to take shape. The eyes and ears form. The eyes move forward on the face, and eyelids form. Pieces of tissue grow and join together to create the forehead, nose, cheeks, lips, and jaw. The nasal passages, mouth, and tooth buds form the baby’s first teeth. A tongue with taste buds also forms.
Arms and legs. At first, the baby’s arms and legs begin as little buds that sprout from the embryo’s sides. As they grow, the arms look like paddles and the legs look like flippers. A ridge appears on the end of each one. They eventually become the baby’s fingers and toes.
Sexual organs. Cells form to become the baby’s eggs or sperm. The baby’s private parts (girl/boy) is visible at the end of the embryonic period.
Muscles and movement. Muscles develop and the embryo begins to move. At first it’s only twitching and reacting to touch. Once the nerves and muscles start working together, the baby can start moving on purpose.
Answer - sea oats
Sea oats play a vital role in the development of sand dunes. The structure of their leaves and roots help in the trapping of the wind blown sand, promoting the growth of sand dunes and their stabilization. Sea oat plantation is encouraged in coastal areas to protect damage from heavy winds and high tide.
