Effectors are

• A) muscles which work in response to the stimulus received from the motor nerves.
• B) glands which work in response to the stimulus received from the motor nerves.
• C) muscles or glands which work in response to the stimulus received from the motor nerves.
• D) efferent neurons

In vascular plants, the sieve tubes and companion cells are present in the

• A. cambium
• B. cortex
• C. xylem
• D. phloem

The group mollusca is characterized by the presence of

• A. jointed appendages
• B. star-shaped bodies
• C. backbones
• D. Soft, non-segmented

The nitrogenous substance that is excreted by birds in order to conserve water is

• A. ammonia
• B. urea
• C. uric acid
• D. nitric acid

Which of the following instruments is used to estimate the number of plants in a habitat?

• A. pooter
• B. pitfall trap
• C. quadrant
• D. sweep net

In the structure of DNA, which of the following statements is true?

• A. The double helix are held together by covalent bonds
• B. Nucleotide is made up of ribose, phosphate and an organic nitrogen compound
• C. Guanine is the opposite of cytosine
• D. Adenine is the opposite of cytosine

The part of the human gut that has an acidic content is the?

• A. stomach
• B. duodenum
• C. ileum
• D. colon

which of the following statements about living things is correct?

• A. animals respire using carbon(iv)oxide as a raw material
• B. growth in plants is limited after some time
• C. most plants respond to stimulus slowly
• D. higher animals can reproduce asexually

The number of plant species obtained from a population study of a garden is as follows: Guinea grass (15), Ipomoea spp (5), Sida spp (7) and Imperata spp (23) What is the percentage of occurrence of Imperata spp?

• A. 35%
• B. 16%
• C. 46%
• D. 23%

The process by which plants manufacture food from carbon dioxide and water using energy from the sun is called

• A. chemosynthesis
• B. photosynthesis
• C. anabolism
• D. catabolism