Biology Test 3
Which nerves send messages from all the senses to the brain?
  • Sensory nerves
  • Mixed nerves
  • None of these
Explanation: Sensory nerves are responsible for sending messages from all the senses to the brain. These nerves carry information about touch, temperature, pain, and other sensory stimuli from various parts of the body to the central nervous system.
What is the excretory unit in the human excretory system?
  • Neuron
  • Nephron
  • Nephridia
  • Nerve
Explanation: The nephron is the functional and structural unit of the human excretory system. Each kidney contains approximately one million nephrons, which filter blood to remove waste products and excess substances, forming urine.
Which hormones are produced by the ovaries?
  • Estrogen
  • Progesterone
  • Both 1 and 2
  • Neither 1 nor 2
Explanation: The ovaries produce both estrogen and progesterone. Estrogen is involved in the development of female secondary sexual characteristics and the regulation of the menstrual cycle, while progesterone helps prepare the uterine lining for pregnancy and regulates the menstrual cycle.
Commonest mammal is ____:
  • Elephant
  • Lion
  • Human
  • Panther
Explanation: Humans are the most common mammal in terms of population. As of 2024, the human population exceeds 8 billion people, making us the most numerous mammal species on Earth.
What is the full form of DNA?
  • Di-nucleic acid
  • Dual nitrogen acid
  • Di-ribonucleic acid
  • De-oxyribonucleic acid
Explanation: DNA is a crucial macromolecule, alongside RNA, proteins, lipids, and carbohydrates, for life as we know it. It encodes the genetic blueprint for living organisms and is involved in many vital biological processes. DNA's structure, a double helix, allows it to store and transfer genetic information efficiently.
What is the main function of white blood cells (WBCs)?
  • To fight against infection
  • To transport oxygen
  • Blood clotting
  • To provide red colour to blood
Explanation: White blood cells are a crucial part of the immune system, defending the body against pathogens like bacteria, viruses, and other harmful organisms.
Plant tissues are of how many types?
  • 3
  • 4
    • Explanation: Plant tissues can indeed be categorized into three main types: Dermal Tissue: This outer layer protects the plant and helps reduce water loss. Vascular Tissue: Includes xylem and phloem, which are involved in the transport of water, nutrients, and food throughout the plant. Ground Tissue: Found between the dermal and vascular tissues, it is involved in photosynthesis, storage, and support. These three types of tissues work together to maintain the plant's structure, function, and overall health.