Answer:
A higher rate of concordance in monozygotic twins in comparison to dizygotic twins is a proved evidence of the contribution of the genetic constituent as monozygotic twins are genetically more identical in comparison to dizygotic twins. The monozygotic twins share all the genes in common and dizygotic twins on average share half of their genes in common.
Thus, the concordance in monozygotic twins is more in comparison with that of dizygotic twins, which shows the contribution of genetics to this trait.
Answer: External intercoastal muscles increase the size of thorasic cavity during inhalation.
Explanation:
Inhalation is the process of breathing in oxygen.
During inhalation, diaphragm contracts and it lead to the expansion of lung volume. When diaphragm contracts, it moves to the abdominal cavity which create a large thorasic cavity . when the external intercoastal muscles contracts, it cause toward and downward movement of the ribs, which cause the rib cage to expand , thereby leading to increase in size of thorasic cavity.
Turn the revolving turret (2) so that the lowest power objective lens (eg. 4x) is clicked into position.
Place the microscope slide on the stage (6) and fasten it with the stage clips.
Look at the objective lens (3) and the stage from the side and turn the focus knob (4) so the stage moves upward. Move it up as far as it will go without letting the objective touch the coverslip.
Look through the eyepiece (1) and move the focus knob until the image comes into focus.
Adjust the condenser (7) and light intensity for the greatest amount of light.
Move the microscope slide around until the sample is in the centre of the field of view (what you see).
Use the focus knob (4) to place the sample into focus and readjust the condenser (7) and light intensity for the clearest image (with low power objectives you might need to reduce the light intensity or shut the condenser).
When you have a clear image of your sample with the lowest power objective, you can change to the next objective lenses. You might need to readjust the sample into focus and/or readjust the condenser and light intensity. If you cannot focus on your specimen, repeat steps 3 through 5 with the higher power objective lens in place. Do not let the objective lens touch the slide!
When finished, lower the stage, click the low power lens into position and remove the slide.
Your microscope slide should be prepared with a coverslip over the sample to protect the objective lenses if they touch the slide.
Do not touch the glass part of the lenses with your fingers. Use only special lens paper to clean the lenses.
Always keep your microscope covered when not in use.
Always carry a microscope with both hands. Grasp the arm with one hand and place the other hand under the base for support.
Answer:
Asexual reproduction is a type of reproduction that doesn’t involve gametes fusing or the change in the number of chromosomes. A spider plant is the perfect example of asexual reproduction, but when it comes to plants like that, it’s referred to a type of asexual reproduction called vegetative propagation.
