Explanation:
Observations of Weather are the Foundation of Climate Products
Cooperative Observers Program (COOP) Stations in the lower 48 states. Image source: COOP
Around the globe, millions of weather observations are recorded each day, by both human observers and automated instruments. In the United States, daily observations at stations that meet specified criteria, methodically collected by volunteer observers and automated weather stations, are used to document our weather and climate. One volunteer weather observer program in the United States is the Cooperative Observer Program (COOP). This program, which includes more than 11,000 stations, is key to obtaining accurate observations across the country. Started in 1890, the COOP network now spans all corners of our nation: from mountaintops to meadows, urban to rural regions, and from seashores to suburbs.
Answer:
The correct option is - (a) the activation and inactivation gates must both be open.
Explanation:
Option (a) is correct because of the following reason -
The axonal membrane is at its natural resting potential until an action potential occurs, and 
channels are deactivated and blocked on the extracellular side by their activation gates. The activation gates open in response to an electric current, allowing positively charged ions to flow into the neuron through the channels. When enough has penetrated the neuron and the membrane potential has reached a certain level, the channels inactivate themselves by closing their inactivation gates at the height of the action potential. The inactivation gate can be thought of as a "plug" tethered to the intracellular alpha subunit's domains III and IV. When the inactivation gate is closed, the flow of through the channel is stopped. As a result, both the activation and inactivation gates must be open to enable sodium ions to enter the cell.
<u>Hence , the correct option is (a).</u>
one is relative to whats happening now and the other is what happened in the past hope this helped!
Answer: The correct answer is Mitosis.
Mitosis is a type of cell division in which parent cell is converted into two daughter cells having same number of chromosomes as that of the parent cell.
It is divided into the following stages-
1) Prophase- It is the first phase of mitosis in which condensation of chromosomes ( clearly visible chromosomes with sister chromatids) takes place and the nuclear membrane is disappeared.
2) Metaphase- It is the second phase in which chromosomes are aligned at the equatorial plate of the cell and they are anchored by microtubules from opposite poles.
3) Anaphase- It is the third phase in which each sister chromatid of the chromosome is pulled apart ( with the help of microtubules) towards the opposite pole.
4) Telophase- Chromosome decondensation takes place and nuclear membrane is formed so that two nuclei are visible now.
5) Cytokinesis- It is the last phase of mitosis in which division of cytoplasm takes place so that two daughter cells are produced having same number of chromosomes as their parent cell.
