3.1.1 During which month was the abscisic acid concentration the lowest? 3.1.2 Explain the trend of the graph from March to May - NSC Life Sciences - Question 3 - 2023 - Paper 1

From March to May, the concentration of abscisic acid increases steadily. This rise can be attributed to environmental factors such as increased sunlight and favorable growth conditions that stimulate the production of abscisic acid in the cherry tree.

One reason for dormancy in cherry trees during winter months is decreased sunlight and lower temperatures, which leads to reduced photosynthesis and lower energy demand, allowing the tree to conserve resources during unfavorable conditions.

Auxins play a crucial role in promoting root development by stimulating elongation of the root cells, which leads to downward growth and positive geotropism. They help roots grow downwards in response to gravity, ensuring the plant can secure itself and access water and nutrients.

In the stem, auxins accumulate on the lower side, stimulating upward growth, while in the roots, auxins also accumulate on the lower side but inhibit growth, causing the roots to bend downward and grow towards the soil.

The gland that secretes aldosterone is the adrenal gland.

The independent variable is the aldosterone level.

The dependent variable is blood pressure.

1. The large sample size of 1,688 volunteers increases the statistical reliability of the results.
2. The consistent methodology across all participants ensures that the results are not influenced by variations in procedure.

1. To control for dietary factors that could influence blood pressure, ensuring that changes can be attributed to aldosterone levels.
2. To maintain consistency in the investigation, which increases the validity of the results by eliminating external variables.

Participants' blood pressure was measured beforehand to establish a baseline level. This allows for comparison to be made after aldosterone injection, ensuring that any observed changes can be attributed to the treatment.

Aldosterone increases the permeability of the renal tubules to salt, which allows for greater reabsorption of sodium back into the bloodstream. As a result, less salt is excreted in the urine, leading to decreased urinary salt levels.

During an emergency, adrenaline is released, which converts glycogen stored in the liver to glucose. This increase in blood glucose level provides immediate energy to muscles. Additionally, adrenaline enhances heart rate, respiratory rates, and metabolic functions, optimizing the body’s response to stress.

Structure F is the iris.

1. Fluid A helps to maintain the shape of the eye.
2. It facilitates the transmission of light by providing a medium for refraction.

Area B contains a high concentration of photoreceptors, specifically rods and cones, which are crucial for detecting light and color. In contrast, area C contains fewer photoreceptors and is less specialized for vision.

The visual defect is astigmatism.

If cataracts develop in part D, the lens becomes cloudy or opaque, which restricts the amount of light that can enter the eye. This results in blurred vision and can significantly affect the clarity of images the person sees.

When an object is less than 6 metres away, the ciliary muscles contract, causing the lens to become more rounded. This increased curvature helps to refract light more strongly, allowing for clear focus on nearby objects.