Correct Answer: D. current accounts

Correct Answer: A. Both pH and temperature

Explanation

Both pH and temperature can affect how productive an enzyme is. If an enzyme is functioning in an environment that is not at its optimal pH or optimal temperature, the enzyme's activity will decrease.

Correct Answer: D. industral waste

Correct Answer: A. erythrocytes

Correct Answer: B. an excellent spirit was in him

Correct Answer: D. Rice

Correct Answer: C) Lewis acid

Correct Answer: A. hair

Correct Answer: D) snail

Explanation

In Biology, animals can have different types of skeletons, one of which is called a jointed skeleton. This type of skeleton is made up of segments that are connected by joints, allowing for flexibility and movement. The question is asking which animal does not have a jointed skeleton. Out of the options given, cockroach, spider, and millipede are all examples of animals that have jointed skeletons. However, snails do not have jointed skeletons, which is why option D is the correct answer. It is worth noting that snails have a hard external shell that protects their body, but this is not the same as a jointed skeleton. In fact, snails belong to a group of animals called mollusks, which have a different type of body structure compared to insects and arachnids. Understanding the different types of skeletons and body structures is important in Biology, as it helps us to classify and understand the diversity of animal life on Earth.

Explanation

(a)(i) Hooke's Law: This states that provided the elastic limit is not exceeded, the extension or compression of an elastic material is directly proportional to the applied force. (ii) Calculation of force constant (K): From Hooke's law:

Mg = Ke = k(l - lo)

0.3 x 10 = k(0.20- lo).. ..(i)

1.95x 10 = k(0.75 - lo) 1) ...(ii)

From (i) lo = \(\frac{3+0.20 k}{lo}\)

From (ii) 19.5 k[0.75 - 0.2 - 3/k]

: K = 30N/m

lo = 0.2 - 3/20

: lo = 0.2 - 0.1 = 0.1m

(b)(i) Definition of diffusion: This is the intimate mixing of substance due to random motion of their molecules/particles.

(b)(ii) Factors that affect the rate of diffusion: (i) Temperature of the environment. (ii) Density of the substance. (iii) Medium of diffusion. (iv) Concentration gradient.

(b)(iii) Relationship between rate of diffusion of a gas and its density:

Rate of diffusion = \(\frac{1}{√density of gas}\)

(c) Derivation of the relationship between the period T, of orbit and R:

\(\frac{MV^2}{R}\) = \(\frac{GMM}{R^2}\)

\(\frac{2πR}{T}\) = \(\frac{GM}{R}\)

\(T^2\) = \(\frac{4π^2R^3}{GM}\)

\(T^2\)α\(R^3\)