Biology - Study Mode

[#486] White blood cell act
Correct Answer

(A) As a defence against infection

Explanation

Solution: White blood cell, also called leukocyte or white corpuscle, a cellular component of the blood that lacks hemoglobin, has a nucleus, is capable of motility, and defends the body against infection and disease by ingesting foreign materials and cellular debris, by destroying infectious agents and cancer cells.

[#487] The top chambers of human heart are called
Correct Answer

(B) Atrium

Explanation

Solution: The top chambers of human heart are called atrium.

[#488] Reflex actions are controlled by :
Correct Answer

(B) The Spinal Chord

Explanation

Solution: A reflex arc is a neural pathway that controls a reflex. In vertebrates, most sensory neurons do not pass directly into the brain, but synapse in the spinal cord. This allows for faster reflex actions to occur by activating spinal motor neurons without the delay of routing signals through the brain.

[#489] Which one of the following is not an insect:
Correct Answer

(D) Spider

Explanation

Solution: Spiders are arachnids. So are scorpions, mites, and ticks. Arachnids are classified primarily by having eight legs and two distinct body regions, the cephalothorax (which is a fusion of the head and thorax), and the abdomen.

[#490] Which cell organelles are involved in photosynthesis?
Correct Answer

(A) Chloroplasts

Explanation

Solution: In plants, photosynthesis takes place in chloroplasts, which contain the chlorophyll. Chloroplasts are surrounded by a double membrane and contain a third inner membrane, called the thylakoid membrane, that forms long folds within the organelle.