Answer:
True
Explanation:
Chiasma is the site of crossing over. It is an X-shaped site that appears in a tetrad (bivalent) chromosome during the diplotene stage of prophase I of meiosis I. Crossing over refers to the exchange of segments of chromatids and occurs between homologous chromosomes only. Crossing over is the event of prophase I of meiosis I and produce new gene combinations.
The homologous chromosomes are separated from each other but remain attached at chiasmata. The dissolution of chiasmata occurs by the end of prophase I and separates the homologous chromosomes completely from each other. Crossing over does not occur in mitosis. Since mitosis does not include crossing over, chiasmata are also not formed in mitosis.
Answer:
A
Explanation:
Tilling agitates the topsoil and removes ‘unnecessary’ vegetation so the main crop can grow without competition. Tilling improves soil aeration and drainage for plants to grow well. Nonetheless, it can lead to other consequences such as soil erosion because it loosens the soil and makes it easy to be carried away by wind and water.
An adult sponge reproduces by mitosis, or cell division.
Answer:
Due to different grouping style
Explanation:
There are two modes of classifying an organism due to which two different cladogram are produced-
A) When the organisms are grouped together on the basis of similarities shared by them – Such species are named based on the name of older species and the newly discovered species sharing similar traits are kept under older species thereby dropping its own name.
B) In the second method, the minute differences are observed in species to group them into several branches arising from one parent organism.
Answer:
E. thickening of the tunica intima and loss of elasticity in the tunica media.
Explanation:
Arteriosclerosis is characterized by thickening of the tunica intima and loss of elasticity in the tunica media.
