Correct Answer: D) Constantly absorb water

Explanation

The xylem is a type of plant tissue that is responsible for transporting water and minerals from the roots to other parts of the plant. However, in addition to its transport function, the xylem also provides support to the plant. The question asks why this is the case, and presents four possible options to choose from. Option A suggests that the xylem is located internally, Option B suggests that it is tubular, and Option C suggests that it has rigid thick walls. However, the correct answer is Option D, which states that the xylem constantly absorbs water. The absorption of water by the xylem causes it to become rigid and stiff, providing support to the plant. This is because water molecules are attracted to each other and tend to stick together, a property known as cohesion. As water is absorbed into the xylem, the cohesive forces between water molecules cause the xylem to become turgid and rigid, which in turn helps to support the plant. It's important to note that while all of the options presented in the question may have some relevance to the xylem's role in supporting plants, only Option D is the correct answer. To learn more about this, please read the relevant sections of the recommended textbooks.

Correct Answer: C. Urea

Correct Answer: B. density

Correct Answer: D. meiosis

Correct Answer: D. vestibular system

Correct Answer: C. Landsteiner and Lavine

Correct Answer: B) gibberelin

Explanation

Some plants are naturally small or dwarf, but it is possible to stimulate them to grow to normal height. The question asks which substance can be applied to a dwarf plant to make it grow to normal height. The options are thyroxin, gibberelin, insulin, and kinin. Thyroxin is a hormone produced by the thyroid gland in animals, and has no effect on plants. Insulin is a hormone produced by the pancreas in animals, and also has no effect on plants. Kinin is a plant hormone that is involved in stress responses and growth regulation, but it does not stimulate growth to normal height in dwarf plants. The correct answer is gibberelin. Gibberelin is a plant hormone that promotes stem elongation and cell division, and can stimulate dwarf plants to grow to normal height. It is used in agriculture to increase the height of crops such as rice and wheat, and in horticulture to promote growth in ornamental plants. In summary, the substance that can be applied to a dwarf plant to make it grow to normal height is gibberelin, which is a plant hormone that promotes stem elongation and cell division.

Correct Answer: B. Eye, cerebellum and ear

Explanation

An individual was involved in a car accident and the illustrated structure was badly injured. Which of the following structures would most likely be affected?

Correct Answer: B. discoid and enucleated

Correct Answer: A) sympathetic and parasympathetic systems

Explanation

The question is asking about the autonomic system in mammals. The autonomic system is responsible for controlling involuntary actions in the body such as heart rate, breathing, and digestion. The options given are: sympathetic and parasympathetic systems, brain and spinal nerves, brain and cranial nerves, and spinal cord and spinal nerves. The correct answer is option A, which states that the autonomic system in mammals consists of sympathetic and parasympathetic systems. The sympathetic system is responsible for the fight or flight response, which prepares the body for action in response to stress or danger. The parasympathetic system, on the other hand, is responsible for the rest and digest response, which helps the body to relax and recover after a stressful event. It is important to note that the autonomic system is part of the peripheral nervous system, which is responsible for transmitting information between the central nervous system (brain and spinal cord) and the rest of the body. The brain and cranial nerves and spinal cord and spinal nerves mentioned in the other options are also part of the peripheral nervous system, but they are not specifically related to the autonomic system. In summary, the correct answer to the question is option A, which states that the autonomic system in mammals consists of sympathetic and parasympathetic systems.