Answer:
Option-D
Explanation:
A reflex arc is the neuron pathway which is involved in producing the response to reflex action or the immediate response.
The reflex arc pathway involves the sensory neurons, interneurons and the motor neurons.
Although the reflex arc pathway involves the brain later but in producing response the brain is not involved.
The stimuli are perceived by the spinal cord but not the brain therefore the selected option is correct.
Thus, option-D is correct.
Ans.
Meiosis involves a type of cell division in sexually reproducing organisms that results in formation of four daughter cells from a single parent cell, having half of the genetic material as in parent cell. Meiosis is divided into meiosis I and meiosis II.
In gamete forming cells of humans are diploid cells and have 23 pairs of chromosomes (or 46 chromosomes). Each gamete forming mother cell undergoes meiotic division to form haploid daughter cells or gametes, each with 23 chromosomes.
Thus, the correct answer is 'twenty-three' as there are 23 chromosomes present in human sex cells at the end of meiosis II.
