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Like red cells, platelets (thrombocytes) have no nucleus. However, unlike red cells that originate in the marrow as nucleated cells and lose their nucleus, platelets are produced by budding off from a giant multinucleated marrow cell called a megakaryocyte.

Ozone sits in the upper atmosphere and absorbs ultraviolet radiaton, another type of solar energy that's harmful to humans, animals and plants. CFCs and halons cause chemical reactions that break down ozone molecules, reducing ozone's ultraviolet radiation-absorbing capacity Chlorofluorocarbons (CFCs) and other halogenated ozone depleting substances (ODS) are mainly responsible for man-made chemical ozone depletion.

The giraffe’s long neck is a perfect adaptation to the animal’s natural habitat. Clearly the giraffe evolved this uncommon and helpful trait in order to reach those nourishing leaves. That’s how natural selection works. Use and disuse' theory in human life advocate the idea that animals acquired characteristics after using certain physical traits constantly.

No expanded working has been attached for this question yet. The verified answer is Option C.

Euglena can survive in a dark room for a long time because it has the ability to switch from photosynthetic (using light) to heterotrophic or holozoic nutrition (absorbing nutrients from the surrounding environment) when deprived of light; essentially acting like a tiny animal by consuming organic matter in the water, allowing it to continue living even without photosynthesis through its chloroplasts.

EXCELLENCE It is a ten-letter word = 10! Since we have repeating letters, we have to divide to remove the duplicates accordingly. There are 4 Es, 2 Cs, 2 Ls ∴ there are: \(\frac{10!}{4!2!2!}\) ways to arrange

Tin is unaffected by air even at ordinary temperature because it forms a thin, protective oxide layer on it's surface. None of the options provided directly explain why tin is unaffected by air. However, for the sake of the examination and choosing the best among the four options, it will be weak electropositive character, as it implies that tin is less reactive.

T = {evenn numbers from 1 to 12} N = {common factors of 6,8 and 12} Find T ∩ N T = {2, 4, 6, 8, 10, 12} N = {2} T ∩ N = {2} i.e value common to T & N

2, 1, \(\frac{1}{2}\), \(\frac{1}{4}\)..... There are 4 terms in the series Therefore the next number will be the 5th term Tn = ar\(^{n − 1}\) (formular for geometric series) a = first term = 2 r = common rate = \(\frac{\text{next term}}{\text{previous term}}\) = \(\frac{1}{2}\) n = number of terms T5 = 5th term = ? T5 = ar\(^{5 - 1}\) = ar\(^4\) = 2 × (ar\(^{n − 1}\))4 = 2 × \(\frac{1}{16}\) = \(\frac{1}{8}\)

U = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20} E1 = {3, 6, 9, 12, 15, 18} E2 = {4, 8, 12, 16, 20} Probability of E2 = \(\frac{5}{20}\) i.e \(\frac{\text{Total number in}E_2}{\text{Entire number in set}}\) Probability of set E2 = 1 − \(\frac{5}{20}\) = \(\frac{15}{20}\) = \(\frac{3}{4}\)

Curved surface area of cylinder = 2πrh 110 = 2 × \(\frac{22}{7}\) × r × 5 r = \(\frac{110 \times 7}{44 \times 5}\) = 3.5cm

Y = Px2 + q Y = 2x2 - 1 Px2 + q = 2x2 - 1 Px2 = 2x2 - 1 - q p = \(\frac{2x^2 - 1 - q}{x^2}\) at x = 2 P = \(\frac{2(2)^2 - 1 - q}{2^2}\) = \(\frac{2(4) - 1 -q}{4}\) = \(\frac{8 - 1 - q}{4}\) P = \(\frac{7 - q}{4}\)

hypotenuse sin = \(\frac{1}{2}\) \(\sin45 = \frac{1}{\sqrt{2}}\) = \(\frac{2}{2}\) ∴ (sin45 + sin30) = \(\frac{1}{\sqrt{2}} + \frac{1}{2}\) = \(\frac{\sqrt{2}}{2}\) + \(\frac{1}{2}\) = \(\frac{\sqrt{2} + 1}{2}\) = \(\frac{1 + \sqrt{2}}{2}\)

y = xsinx \(\frac{dy}{dx}\) = \(1 \sin x + x \cos x\) = \(\sin x + x \cos x\) At x = \(\frac{\pi}{2}\) = sin\(\frac{\pi}{2}\) + \(\frac{\pi}{2} \cos {\frac{\pi}{2}}\) = 1 + \(\frac{\pi}{2}\) \times 0 = 1

t ∝ h, t = 20, h t = ? h = 60 t = kh where k is constant 20 = 50k k = \(\frac{20}{50}\) k = \(\frac{2}{5}\) when h = 60, t = ? t = \(\frac{2}{5}\) × 60 t = 24oC