Muscle contraction is initiated by a signal sent by the central nervous system by the release of

Given below are two statements: Statement I: When any plane passing through the central axis of the body divides the organism into two identical halves, it is called radial symmetry. Statement II: In phylum Echinodermata, both adults and larvae are radially symmetrical. In the light of the above statements, choose the most appropriate answer from the options given below:

The numbers 17.0145 and 21.0235 were rounded to three figures after the decimal point. The resulting numbers, respectively, are

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R. Assertion A: The logistic growth model of populations is considered more realistic than the exponential growth model. Reason R: Resources are finite. In the light of the above statements, choose the most appropriate answer from the options given below:

Consider two circuits, (A) and (B), each having two resistors. One of them has a positive temperature coefficient of resistance, +$\alpha$, while the other one has a negative temperature of coefficient, -$\alpha$, as shown in the figure. The current through these circuits are denoted by $I_{A}$ and $I_{B}$. At initial temperature, the resistance of the two resistors is $R_0$. As the temperature is increased, the correct option that describes the variation of current in these circuits is: