The original six frigates of the United States Navy<span> came up with the Naval Act of 1794. Two<span> characteristics are distinct of these said early US. Navy "super frigates. They are: </span></span>
<span>· </span><span>timbers put close together to be able to withstand heavy cannon fire</span>
<span>· </span><span>hull reinforced to resist the pressures of heavier ordnance on deck</span>
Cyclins
are the chemicals that regulate the cell cycle. Cyclins work by regulating the timing
of the cell cycle in eukaryotic cell. Cyclins activates cyclin dependent
kinases (CDKs) (an enzyme that works by adding <span>negatively charged phosphate groups to other
molecules in a process called phosphorylation) by binding to it to form a cyclin-Cdk
complex. This complex then functions by acting as a signal to the cell to move
to the next cell cycle phase. At the end of the event, the cyclin is degraded, Cdk
is deactivated, therefore signaling exit from a specific phase.</span>
Answer: A. scalp hairs grow constantly throughout life.
Explanation:
Hair is a squamous keratinized epithelium which is consist of multi-layered flat cells. Hair are made up of protein called "keratin".
The statement "scalp hairs grow constantly throughout life" is false because at a particular age or due to several factors scalp hairs stop growing.
Scalp hair growth rate depends on three main factors including sex (female hair grows faster than male), age (hair growth slows with age), and ethnicity (Asian hair grows slower than Caucasian hair).
Scalp hair growth stops because of follicle devitalization when the hair length become two or three feet.
Hence, the correct answer is A. "scalp hairs grow constantly throughout life".
Answer:
True
Explanation:
When the resting potential of the membrane is changed, the membrane becomes either more negative inside or less negative. This small deviation from the resting potential is called graded potential. A graded potential occurs when a stimulus triggers opening or closing of the mechanically gated or ligand-gated channels present in the plasma membrane.
For example, the presynaptic neuron releases neurotransmitters in response to a nerve impulse. The neurotransmitter binds to receptors present in the plasma membrane of the postsynaptic neuron and triggers the opening of the ion channels to allow the inflow of particular ions to flow. The flow of ions changes the voltage across the membrane. This change in membrane voltage is a postsynaptic potential and is a type of graded potential.
