Practice MCQ Questions and answers on Biology-GK

The zygosity of F₁ generation can be checked by test cross method. In a test cross : The organism with the dominant trait is always crossed with an organism with the recessive trait. If any offspring show the recessive trait, the unknown genotype is heterozygous.
If all the offspring have the dominant trait, the unknown genotype is homozygous dominant.
Large numbers of offspring are needed for reliable results.

A colour blind person cannot see any colors is not true of colour blindness.

Stem Cell Therapy (SCT) is not useful for the treatment of Vision impairment.

When there is bright light, the iris closes the pupil to let in less light. And when there is low light, the iris opens up the pupil to let in more light. Focuses light rays onto the retina.

The minimum distance from the eye at which an object appears to be distinct i.e., a very clear image of the object is formed is called the distance of distinct vision. This distance is about 25 cm from the eye.

The eye has three main layers. These layers lie flat against each other and form the eyeball. The outer layer of the eyeball is a tough, white, opaque membrane called the sclera (the white of the eye). The slight bulge in the sclera at the front of the eye is a clear, thin, dome-shaped tissue called the cornea.

Normal cones and pigment sensitivity enable an individual to distinguish all the different colours as well as subtle mixtures of hues. This type of normal colour vision is known as trichromacy and relies upon the mutual interaction from the overlapping sensitivity ranges of all three types of photoreceptor cone.

Three layers of membranes known as meninges protect the brain and spinal cord. The delicate inner layer is the pia mater. The middle layer is the arachnoid, a web-like structure filled with fluid that cushions the brain. The tough outer layer is called the dura mater.

The pia mater is the innermost layer of meninges. This thin, delicate membrane is tightly bound to the surface of the brain and spinal cord and cannot be dissected away without damaging the surface. Meningiomas are tumors of the nerve tissue covering the brain and spinal cord.

The nervous system has two main parts: The central nervous system is made up of the brain and spinal cord. The peripheral nervous system is made up of nerves that branch off from the spinal cord and extend to all parts of the body.