Answer: A
Explanation: Ripple marks are sedimentary structures and indicate agitation by water (current or waves) or wind.
<h2>Answer:</h2>
Bt corn is a genetically modified organism that contains a gene of bacteria known as Bacillus thuringiensis.
<h3>Explanation:</h3>
- Bt corn is a type of transgenic crop that contains a gene which produces a crystal-like protein which has an insecticidal effect.
- This gene is present in bacteria. This gene is transferred to the plant by the recombinant DNA technology and genetic engineering.
- This bacterium is a soil bacterium which has no side effects on humans.
- Due to use of this technology, the poisonous chemical insecticides are not used in crop production.
There are choices for this question namely:
<span>a. K+ leaks into cells.
b. Voltage-gated Na+ channels become inactivated.
c. Voltage-gated K+ channels become inactivated.
d. Na+ reaches equilibrium across the neural membrane and stops leaking in.
e. Voltage-gated Na+ channels close.
The correct answer is "voltage-gated Na+ channels become inactivated". In the events concerning an action potential, the first event is a stimulus that depolarize the resting membrane potential up to the threshold. When the threshold is reached there will be opening of voltage gated Na+ channels wherein sodium can enter the cell and make the membrane more positive therefore called depolarization. After depolarization, voltage gated Na+ channels become inactivated and K+ leaks out of the cell making the cell less negative hence repolarization. After which, more and more K+ ions leaks out making the membrane more negative than the resting membrane potential hence hyperpolarization. When K+ channels are inactivated, the cell membrane will eventually go back to its resting membrane potential.</span>
