Answer:
The membrane potential of a resting neuron is primarily determined by the movement of K+start text, K, end text, start superscript, plus, end superscript ions across the membrane. ... Zero voltage across the membrane, as measured by a voltmeter with one electrode inside and one electrode outside the cell.
For the first question, I would say a line graph. And the one about the human heart, I need some more information.
Answer: D. An adaptive process that allows children to deal more efficiently with their environment.
Explanation:
Synaptic pruning is a natural process between early childhood and adulthood which occurs in the brain. The brain removes the extra synapses during synaptic pruning. Synapses are brain structures that allow the neurons to transmit to another neuron an electrical or chemical signal.
Synaptic pruning is thought to help the brain transition from adolescence, when it can quickly learn and make new connections, to adulthood, when it is much more stable in its structure, but can concentrate on a single question for longer and conduct more complex thinking processes. Synaptic pruning make brain more adaptive to the external environment in early ages.
Hence, the correct option is D. An adaptive process that allows children to deal more efficiently with their environment.
Answer: "Decreasing the salt concentration of the solution lowers DNA's melting point (Tm)" is not a true statement
Explanation:
Increasing salt concentration would lower the DNA's melting point (Tm), not otherwise.
For instance:
- In 8M urea (8M means 8 Moles per dm3), Tm is decreased by nearly 20°C.
- 95% formamide at room temperature would completely denature the double stranded DNA.
Thus, higher concentration of salts like urea or formamide lowers Tm, not otherwise
Answer:
Option (2).
Explanation:
Ames test is used to identify the mutageneicity of the compound. The bacteria are treated with chemicals in the nutritive environment to determine whether the substance can acts as a mutagen or not.
The bacteria that can restore the biosyntheic activity in the environment can be considered as mutagen. The mutant bacteria can be easily identified in the Ames test.
Thus, the correct answer is option (2).
