Answer:
Contains large polytene chromosome that permit visual inspection of genomic events.
Were used to study the genetic effects of mutations.
Were used to establish the concept of chromosomal inheritance.
Explanation:
<em>Drosophila melanogaster </em>is a model organism that is used by scientists to study the genes and effect of a mutation on the genes. Drosophila is used as a model organism as it has a very short life cycle and the offspring can be produced in a short duration of time.
Because of these characteristics, Thomas Hunt Morgan wanted to study the factors of inheritance on the <em>Drosophila</em> and concluded in the form of the chromosomal theory of inheritance by the effect of mutation on genes that lead to linkage mapping.
Also, the salivary gland of fruit fly contains the polytene chromosome which allows us to look into the gene events.
Thus, the selected options are correct.
Answer:
The air
Explanation:
the air has a component of 79% of nitrogen gas (N2)
Answer:
Explanation:
1. Latitude or distance from the equator – Temperatures drop the further an area is from the equator due to the curvature of the earth. In areas closer to the poles, sunlight has a larger area of atmosphere to pass through and the sun is at a lower angle in the sky.
2. Altitude or height (also sometimes known as depth) is a distance measurement, usually in the vertical or "up" direction, between a reference datum and a point or object. The exact definition and reference datum varies according to the context (e.g., aviation, geometry, geographical survey, sport, or atmospheric pressure). Although the term altitude is commonly used to mean the height above sea level of a location, in geography the term elevation is often preferred for this usage.
3. Large bodies of water, such as oceans, seas and large lakes, can affect the climate of an area. Water heats and cools more slowly than landmasses. Therefore, the coastal regions will stay cooler in summer and warmer in winter, thus creating a more moderate climate with a narrower temperature range.
4. Ocean currents can be caused by wind, density differences in water masses caused by temperature and salinity variations, gravity, and events such as earthquakes or storms. Currents are cohesive streams of seawater that circulate through the ocean
Answer and Explanation:
The retina covers the internal phase of the eye. It characterizes by its complex interaction between many morphologically and functionally different cells, which are located in many layers. The principal processing mechanism in the retina is lateral interactions among cells, and the most common lateral processing is lateral inhibition.
Photoreceptors are those cells that receive the light and translate the luminous signal into an electrical signal. These are the cones and sticks.
The horizontal cells intervene in the lateral spatial interaction between photoreceptors.
Bipolar cells receive information from the photoreceptors and from the horizontal cells and transmit it to the most internal layers in the retina.
The retina is stratified into five layers. One of these is the external plexiform layer, a contact zone between photoreceptors, horizontal cells, bipolar cells, and other cells.
In the vertebrates´ retina, the lateral inhibition is produced for the first time in the external plexiform layer, through the horizontal cells. These cells connect to photoreceptors, other horizontal cells, and bipolar cells. The connection between horizontal cells might reduce or amplify the photoreceptor answer, and this last one is transmitted by the bipolar cells to the interior of the retina. In photoreceptors, there are two connections to horizontal cells, a direct connection, and an indirect one. The connection between photoreceptors, horizontal cells, and bipolar cells is known as lateral inhibition. By this inhibition, photoreceptors allow the contrasting perception in an image. Lateral inhibition allows discriminating one stimulus from other stimuli, by enhancing contrast and definition. The inhibitory modulation is produced by the inhibitor neurotransmitter GABA.The spacial extension of lateral inhibition changes according to the adaptation to light. Gap junction between horizontal cells and between photoreceptors and horizontal cells might vary with the amount of light.