Answer:
x4 objective
Explanation:
The student should use the x4 objective lense in order to be able to observe the palisade cell of a leaf.
<em>The palisade cells are located below the cuticle and the epidermis of the leaf and the x4 objective will provide the largest field of view for adequate study by the student. The x4 objective is also easier to focus compared to the lower objectives.</em>
The tigers have stripes because it is advantageous for them because they are an ambush predator and need good camouflage. The stripes are excellent camouflage for places that are shady, so the tiger can easily get close to its prey and attack it.
There's a very big possibility that the distant ancestors of the tigers did not had stripes. The reasons for that are different environment, but also that the stripes are actually a very rare type of pattern among the felidae family members.
As the environment started changing, the tigers needed to adapt to it, so they also needed a different camouflage. As some tigers in the population started to develop stripes, they were better hunters, thus were stronger, and seen as suitable mates for the females, as it would provide an offspring with the advantage that the male tiger has. Through this selection in the breeding process of mates that have advantageous camouflage patterns, the stripes were becoming more and more present, to the point where they totally pushed aside and eliminated the previously dominant camouflage pattern.
A. Hormones act as signal molecules between all body systems
Peripheral Chemoreceptors (Carotid + Aortic Bodies) and Central Chemoreceptors in the Medulla Oblongata detect high Carbon Dioxide levels in the blood during exercise. The respiratory centre in the Medulla Oblongata + PONS stimulate the intercostal muscles and the diphragm to contract in order to increase the rate and depth of breathing as to decrease levels of Carbon dioxide in the blood.
The thyroid gland secretes thyroxine which speeds up metabolism (the rate at which cells use glucose)
