Correct Answer: D. Bird

Correct Answer: C. cellulose cell wall can resist the turgidity

Correct Answer: A. Polythene bag

Correct Answer: D. Presence of a segmented body

Explanation

Arthropods are characterized by the presence of a segmented body. This is a key characteristic of the phylum Arthropoda, which includes insects, spiders, and crustaceans. The other options are incorrect. Arthropods do not exhibit radial symmetry, they have an open circulatory system, and their exoskeleton is made of chitin, not bones.

Correct Answer: C) Sacrum

Explanation

The question is asking which of the following is part of the axial skeleton in a mammal. The axial skeleton is the part of the skeleton that provides support and protection for the central axis of the body. It includes the skull, vertebral column, and rib cage. Option A, phalange, is a bone found in the fingers and toes, and is part of the appendicular skeleton which includes the limbs and girdles. Option B, tarsal, is a bone found in the ankle and is also part of the appendicular skeleton. Option C, sacrum, is the correct answer. It is a large triangular bone at the base of the spine, formed by the fusion of five vertebrae and is part of the vertebral column, which is a component of the axial skeleton. The sacrum connects the spine to the hip bones and helps to transfer weight from the upper body to the lower body. Option D, patella, is commonly known as the kneecap, and is also part of the appendicular skeleton, specifically the leg bones. In summary, the correct answer to the question is Option C, sacrum, which is part of the axial skeleton in a mammal.

Explanation

(a) Formation of zygote in a flower takes place in the following ways:

• The pollen grain absorbs water, sugary fluid and glucose from sticky stigma.
• It swells and germinates.
• Pollen tube emerges, carrying a tube nucleus and a generative nucleus.
• The generative nucleus divides into two male nuclei; it grows down the style and ovary wall.
• It derives energy and food from the tissues, to reach the ovule; It enters ovule through the micropyle; to enter embryo sac;
• Pollen tube releases male nuclei into embryo sac; as tube nucleus degenerates.
• Nucleus of one male gamete fuses with the egg cell in order to achieve fertilization which resulted to the formation of zygote.

(b) Importance of Amniotic sac are as follows:

(i) Amniotic fluid contains the embryos.

(ii) This provides a constant warm temperature for the foetus.

(iii) It provides a sterile environment for development.

(iv) It provides hydrostatic protection against mechanical injury and shock

(v) It allows movement of the foetus.

Correct Answer: A. Cleistogamy

Correct Answer: D. locomotion in organisms

Correct Answer: B. cytoplasmic connections

Explanation

Similar cytoplasmic bridges link the cells of all volvocacean embryos. Neighboring cells are often joined together by strands of cytoplasm.

Correct Answer: C. 2RR, 2Rr