Answer:
I, II, III
Explanation:
A threshold stimulus is a stimulus that is capable to produce a response in excitable tissues such as neurons and muscle fibers. At threshold potential, the outward movement of K+ and inward movement of Na+ become equal to each other. When the potential exceeds the threshold potential, more and more Na+ enter the cell to depolarize it and to allow the opening of Na+ channels. Therefore, to fire an action potential, the threshold must be exceeded.
Conduction of action potential is all or none phenomenon which means that either it occurs or it does not occur. As an impulse is passed by each successive part of an exon, it enters the refractory period during which there is no conduction of nerve impulse. It ensures the one-way conduction of impulse from the cell body to the axon terminal only.
The process is called ovulation
Complete question:
Prophase of meiosis I has some important differences from prophase of mitosis. These differences include: ___________BLANK pair, and _________BLANK occurs.
A: chromatids; condensation
B.,chromosomes; separation
C. homologous chromosomes; crossing over
D. homologous chromatids; separation
Answer:
C. homologous chromosomes; crossing over
Explanation:
Prophase I of meiosis and prophase of mitosis are quite distinct with respect to the events occurring in the cells. Prophase-I of meiosis is a relatively long stage. The Zygotene stage of prophase-I includes the pairing of homologous chromosomes. This pairing is mediated by synaptonemal complex and the process is called synapsis. The paired chromosomes undergo the process of crossing over during the pachytene stage of prophase-I. In crossing over, the non-sister chromatids of the bivalents exchange some genetic material between them. The events of synapsis and crossing over do not occur during prophase of mitosis.
Answer:
Option B and E and D
Explanation:
Technological advancement has led to growth of industries and manufacturing units and hence the net production of goods. This has led to the use of natural resources and release of pollution of all forms. Environmental research leads to intrusion into niche habitats and hence causes its destruction.
Option B, D and E are correct
