Correct Answer: C. Cu (s) + 2HCI (aq) → CuCI 2(aq) + H2(g)

Correct Answer: D. 78°

Explanation

∠ QPR + ∠ PRQ = ∠ RQS

(Sum of two interior angles of a triangle = Opposite exterior angles)

70^o + ∠ PRQ = 148

∠ PRQ = 148^o - 70^o

= 78^o

Correct Answer: C. 3

Explanation

Volume of sphere = Volume of cylinder

i.e. \(\frac{4}{3} \pi r^3 = \pi r^2 h\)

\(\frac{4}{3} \pi r^3 = \pi \times 3^2 \times 4\)

r³ = \(\frac{\pi \times 9 \times 4 \times 3}{4 \pi}\)

r = 3\(\sqrt{27}\)

= 3

Correct Answer: C. denudation

Correct Answer: C. I, IIl and Iv only

Correct Answer: A) Xylem and phloem

Explanation

In plants, the structures that play roles similar to the arteries and veins of animals are called vascular tissues. The two main types of vascular tissues in plants are xylem and phloem. Xylem is responsible for transporting water and minerals from the roots to the leaves, while phloem transports sugars and other organic compounds from the leaves to other parts of the plant. Therefore, the correct answer to this question is option A, xylem and phloem. These structures are essential for the growth and survival of plants, as they allow for the efficient transport of nutrients and water throughout the plant. It is important to note that the other options provided in the question are not correct. Root hairs are extensions of the root epidermis that increase the surface area for absorption of water and minerals, while lenticels are small pores on the stems and roots of some plants that allow for gas exchange. Roots and stems are also important structures in plants, but they do not function in the same way as the arteries and veins of animals. Understanding the functions and structures of vascular tissues is a fundamental concept in plant biology and is relevant in many areas of study, including agriculture, ecology, and biotechnology.

Correct Answer: (c) Verbosity

Correct Answer: B. an invoice

Correct Answer: C. Monopolistic firm

Explanation

Monopolistic firm is characterizes by an industry in which many firms offer products or services that are similar, but not perfect substitutes. Barriers to entry and exit in a monopolistic competitive industry are low, and the decisions of any one firm do not directly affect those of its competitors.

Explanation

(a) \(x = 3i - j ; y = 2i + kj\)

\(x \cdot y = |x||y| \cos \theta\)

\((3i - j) \cdot (2i + kj) = (\sqrt{3^{2} + (-1)^{2}})(\sqrt{2^{2} + k^{2}}) \cos \theta\)

\(6 - k = (\sqrt{10})(\sqrt{4 + k^{2}})(\frac{\sqrt{5}}{5})\)

\(5(6 - k) = \sqrt{10(4 + k^{2})(5)}\)

\(30 - 5k = \sqrt{200 + 50k^{2}}\)

\((30 - 5k)^{2} = 200 + 50k^{2}\)

\(900 - 300k + 25k^{2} = 200 + 50k^{2}\)

\(900 - 200 - 300k + 25k^{2} - 50k^{2} = 0\)

\(25k^{2} + 300k - 700 = 0 \implies k^{2} + 12k - 28 = 0\)

\(k^{2} - 2k + 14k - 28 = 0 \implies k(k - 2) + 14(k - 2) = 0\)

\(\text{k = 2 or -14}\).

(b)

ABCD is a parallelogram if AD = BC.

\(\overrightarrow{AD} = \overrightarrow{AB} + \overrightarrow{BD}\)

= \(\begin{pmatrix} -5 \\ -1 \end{pmatrix} + \begin{pmatrix} 4 \\ -7 \end{pmatrix}\)

= \(\begin{pmatrix} -1 \\ -8 \end{pmatrix}\)

\(\overrightarrow{BC} = \overrightarrow{BA} + \overrightarrow{AC}\)

= \(\begin{pmatrix} 5 \\ 1 \end{pmatrix} + \begin{pmatrix} -6 \\ -9 \end{pmatrix}\)

= \(\begin{pmatrix} -1 \\ -8 \end{pmatrix}\).

\(\overrightarrow{AD} = \overrightarrow{BC}\). ABCD is a parallelogram.