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In a certain plant, red flowers are dominant over white flowers. A plant heterozygous for red flowers and a plant with white flowers are crossed. Which of the following is the expected proportion of phenotypes in the next generation?

A. 3 red, 1 white

B. 1 white, 3 red

C. 2 red, 2 white

D. 4 white

Answer Explanation:

2 red, 2 white.

In this cross, the plant heterozygous for red flowers has the genotype Rr (where R represents the dominant red allele and r represents the recessive white allele), while the plant with white flowers has the genotype rr.

The possible offspring from this cross would have the genotypes Rr (red), Rr (red), rr (white), and rr (white), resulting in a 1:1 ratio of red to white flowers.

 

Therefore, the Correct Answer is C.

More Questions on TEAS 7 Science

  • Q #1: Lithium has an atomic number of 3 and a mass number of 7. Which of the following is the number of neutrons in a lithium atom?

    A. 4

    B. 7

    C. 12

    D. 3

    Answer Explanation

    The atom is identified by the atomic number in the periodic table. The atomic number is equal to the number of protons and mass number is the sum of the number of protons and neutrons in the nucleus of an atom. Thus, to find how many neutrons are in lithium atom we use the formula below.

    Mass number = number of protons + number of neutrons.

    Letting n be number of neutrons in the lithium atom, we have

    7=3+n

    Rearranging the above equation

    3+n=7

    n=7-3

    n=4

    Thus, lithium atom has 4 neutrons.

  • Q #2: Which of the following vessels carries oxygenated blood?

    A. Inferior vena cava

    B. Pulmonary vein

    C. Pulmonary artery

    D. Superior vena cava

    Answer Explanation

    Pulmonary vein carries oxygenated blood from the lungs to the heart. Pulmonary artery carries deoxygenated blood from the heart to the lungs.
    Superior and inferior vena cava bring in deoxygenated blood from all other parts of the body to the heart.

  • Q #3: A myocardial infarction affects which of the following blood vessels of the heart?

    A. Aorta

    B. Vena cava

    C. Pulmonary

    D. Coronary

    Answer Explanation

    A myocardial infarction refers to heart attack, which result from blockage of blood flowing into the heart.

    Blocking is caused by the deposition of fat or cholesterol that forms plaque on the surface of coronary arteries, which supply blood to the heart.

  • Q #4: Which of these infectious agents do not have nucleic acid?

    A. viroids

    B. viruses

    C. bacteria

    D. prions

    Answer Explanation

  • Q #5: Which of the following are structural features of the trachea?

    A. C-shaped cartilage

    B. Smooth muscle fibers

    C. Cilia

    D. All of the above

    Answer Explanation

  • Q #6: Contraction of the external intercostal muscles causes which of the following to occur?

    A. The diaphragm moves downward

    B. The rib cage is compressed

    C. The thoracic cavity volume decreases

    D. The ribs and sternum move upward

    Answer Explanation

    The intercostal muscles are muscles are located along the ribs. The intercostal muscles assist in respiration mechanically. This allows the expansion and contraction of the thorax.
    Contraction of the external intercostal muscle causes the ribs and sternum move upward.

  • Q #7: Which of these processes occurs in the mouth?

    A. Ingestion

    B. Mechanical digestion

    C. Chemical digestion

    D. All of the above

    Answer Explanation

    All of these processes occur in the mouth. Ingestion involves taking food into the mouth, mechanical digestion includes the physical breakdown of food through chewing and mixing with saliva, and chemical digestion begins with the action of enzymes in saliva, such as amylase, which starts to break down carbohydrates.

  • Q #8: In a certain plant, red flowers are dominant over white flowers. A plant heterozygous for red flowers and a plant with white flowers are crossed. Which of the following is the expected proportion of phenotypes in the next generation?

    A. 3 red, 1 white

    B. 1 white, 3 red

    C. 2 red, 2 white

    D. 4 white

    Answer Explanation

    2 red, 2 white.

    In this cross, the plant heterozygous for red flowers has the genotype Rr (where R represents the dominant red allele and r represents the recessive white allele), while the plant with white flowers has the genotype rr.

    The possible offspring from this cross would have the genotypes Rr (red), Rr (red), rr (white), and rr (white), resulting in a 1:1 ratio of red to white flowers.

     

  • Q #9: Which of the following best describes veins?

    A. thick walled, small lumens, low pressure, lack valves

    B. thin walled, large lumens, low pressure, have valves

    C. thin walled, small lumens, high pressure, have valves

    D. thick walled, large lumens, high pressure, lack valves

    Answer Explanation

  • Q #10: The process that moves nutrients into the blood or lymph is

    A. digestion

    B. ingestion

    C. elimination

    D. absorption

    Answer Explanation

    Digestion is the breakdown of large insoluble food molecules into small water-soluble food molecules so that they can be absorbed into the watery blood plasma.

    Ingestion is the process of taking food, drink, or another substance into the body by swallowing or absorbing it.

    Elimination refers to the removal of indigestible wastes through the anus, in the form of feaces.