Nervous Systems in Animals and Plants

What is the main organ for nervous control in vertebrates?

• Brain

• Nervenets

• Vascular strands

• Root tip

Answer explanation

The brain is the main organ for nervous control in vertebrates, coordinating sensory information and motor responses, while the other options do not serve this primary function.

What do invertebrates lack for nervous control?

• Brain

• Nervenets

• Vascular strands

• Root tip

Answer explanation

Invertebrates lack a centralized brain, which is crucial for complex nervous control. Instead, they may have simpler nerve nets or other structures, but the absence of a brain distinguishes them from vertebrates.

What acts as a unit of the serial nervous system in plants?

• Brain

• Nervenets

• Vascular strands

• Root tip

Answer explanation

The root tip acts as a unit of the serial nervous system in plants, coordinating growth and responses to environmental stimuli, unlike the other options which do not serve this specific function.

What carries information from the brain and spinal cord to muscles and glands in animals?

• Nerves

• Vascular strands

• Root tip

• Apices

Answer explanation

Nerves are the structures that transmit signals from the brain and spinal cord to muscles and glands, enabling movement and physiological responses. Therefore, the correct answer is 'Nerves'.

What is positive phototropism?

• Growth toward light

• Growth away from light

• Growth toward gravity

• Growth away from gravity

Answer explanation

Positive phototropism refers to the growth of plants toward light sources. This adaptation allows plants to maximize their exposure to sunlight, which is essential for photosynthesis.

What is positive geotropism?

• Growth toward gravity

• Growth away from gravity

• Growth toward light

• Growth away from light

Answer explanation

Positive geotropism refers to the growth of plant roots toward gravity, allowing them to anchor securely in the soil and access water and nutrients. Thus, the correct answer is 'Growth toward gravity'.

What is positive hydrotropism?

• Growth toward water

• Growth away from water

• Growth toward gravity

• Growth away from gravity

Answer explanation

Positive hydrotropism refers to the growth of plant roots toward water sources. This adaptation helps plants optimize water uptake, making 'Growth toward water' the correct choice.

What is thigmotropism?

• Growth in response to touch

• Growth in response to light

• Growth in response to gravity

• Growth in response to water

Answer explanation

Thigmotropism is the growth of plants in response to touch. This phenomenon allows plants to adapt to their environment by growing around objects they come into contact with, making 'Growth in response to touch' the correct answer.

What is thermotropism?

• Growth in response to temperature changes

• Growth in response to light

• Growth in response to gravity

• Growth in response to water

Answer explanation

Thermotropism refers to the growth of plants in response to temperature changes. This distinguishes it from other tropisms like phototropism (light), gravitropism (gravity), and hydrotropism (water).

Invertebrates, for a lack of a brain, have ____ as their main organ for nervous control.

Answer explanation

Invertebrates lack a centralized brain and instead utilize nerve nets, which are decentralized networks of neurons, for their main nervous control. This allows them to respond to stimuli without a central processing unit.