Ans.1.
Climatic adaptations are defined as adaptions developed in organisms due to variation in climatic conditions, such as change in temperature. White fur of arctic fox and snowshoe rabbit helps them to hide in snow and protects from winter, while, furs in padded feet help them to walk in snow. Hence, these adaptions are examples of adaptations to climate.
Thus, the correct answer is option). climate.
Ans.3.
The sodium-potassium ATPase or sodium-potassium pump is an example of membrane protein that helps in transport of sodium and potassium ions. It pumps three sodium ions outside the cell from cytoplasm and carries three potassium ions inside the cell from extracellular matrix.
It is responsible for creating gradient in the cells between sodium and potassium ions.
Thus, the correct answer is option). sodium.
Ans.4.
The absorption rate of a cell depends upon the surface area-to-volume ratio of that cell. Higher the surface area-to-volume ratio of a cell, higher the absorption would be done by that cell.
The cell surface area-to-volume ratio of cuboid organism with 2 cm each side = 6 x 2 x 2 / 2 x 2 x 2 = 3.
The cell surface area-to-volume ratio of cuboid organism with 1 cm each side = 6 x 1 x 1 / 1 x 1 x 1 = 6.
(As for cubes, surface area = 6 a², while volume = a³, where a = side)
The cell surface area-to-volume ratio of smaller cube organism (with 1 cm each side) is two times more than the larger cube organism (with 2 cm each side). Hence, the smaller cube organism will show two times faster absorption of oxygen.
Thus, the correct answer is option). 2 times.
Ans. 5.
The cell size is regulated to a certain limit in all organisms accordingly. This is because, as the cell gets larger in size, the surface area-to-volume ratio becomes smaller, which decreases efficiency of nutrient absorption as cells with smaller surface area-to-volume ratio show slower absorption of materials.
Hence, if a cell increases its size beyond limit, the plasma membrane would not be able to supply enough nutrients and other substances to the cell.
Thus, the correct answer is option). the cell membrane can't supply enough materials for a too large cell.
