number 2
number 2 because the colour doesnt matter
An isometric exercise is a form of exercise involving the static contraction of a muscle without any visible movement in the angle of the joint.
Answer:
The concentration gradient is the driving force.
Explanation:
Passive transport of substance occurs when they are moved from the region of their higher concentration to that of their lower concentration. The concentration gradient is the difference in the concentration of substances between two regions or across the membrane. The concentration gradient of substances drives their passive movement. The passive movement of substances does not use metabolic energy. Simple diffusion and facilitated diffusion are two examples of this transport.
ANSWER:
Brain cells that are neither neurons nor glia, but which are capable of dividing and then differentiating into neurons or glia, are called NEURAL STEM CELLS.
EXPLANATION:
Neural stem cells are undifferentiated cells originating in the central nervous system.
Neural stem cells (NSCs) have the potential to give rise to the radial glial progenitor cells that grow and differentiate into neurons and glial cells.
NSCs have an important role during development producing the enormous diversity of neurons, astrocytes and oligodendrocytes in the developing CNS.
A NEURON (nerve cell) is a specialized cell that conveys electrochemical impulses throughout the body.
provide support for and insulation between them.
GLIAL CELLS are the most abundant cell types in the central nervous system. Types of glial cells include oligodendrocytes, astrocytes, ependymal cells, Schwann cells, microglia, and satellite cells.
Answer: The correct answer is -
D) giraffes having increasingly longer necks over time.
Natural selection is an evolutionary mechanism that was proposed by Darwin.
According to this mechanism, organisms that are better capable of adapting to their changing environmental conditions, survive and increase their number through reproduction whereas other are eliminated from the population.
Example - Long neck of Giraffe, which is much elongated, lofty stature, that was beautifully adapted for browsing on the higher tree branches. This was an adaptation with slow and gradual change in the gene frequency as the lower vegetation was eaten by other animals. Due to this, giraffes had to search for other source (that was higher tree branches).
This is considered as a peculiar example of natural selection.
