Practice Test - NEET MCQ

To describe motion along a straight line, we can choose an axis, say X-axis, so that it coincides with the path of the object. We then measure the position of the object with reference to a conveniently chosen origin, say O, Positions to the right of O are taken as positive and to the left of O, as negative.

Explanation:Position-time graph of horizontal straight line parallel to time axis represents that the position of the body does not changes with the passage of time. So it represents the rest state of motion.It means velocity of object is zero.

Explanation:To describe motion along a straight line, we can choose an axis, say X-axis, so that it coincides with the path of the object. We then measure the position of the object with reference to a conveniently chosen origin, say O,  Positions to the right of O are taken as positive and to the left of O, as negative.

Explanation:

Acceleration is the rate of change of velocity with time.It is a vector quantity.

Average acceleration is the change in velocity per unit time over an interval of time.

Let initial velocity at time interval t​​​​​​₁ is v​​​​​​₁ and final velocity at time interval t​​​​​₂ is v​​​​​​₂ Then

The law of definite proportions, also known as the law of constant composition states that all pure samples of the same chemical compound contain the same elements combined in the same proportions by mass.
What this law emphasizes is that, if pure samples of the same chemical substance, wherever they may be found, are analyzed, it will be found that they all consist of the same elements, as well as having these elements combine in the same proportions by mass.
For examples, pure sample of copper(II) oxide is composed of copper and oxygen, in the proportion of 1:1 by mole, or 64 g of copper to 16 g of oxygen or 1 g of copper to 0.25 g of oxygen. 

Chemical reactions involve merely the combination, separation, or rearrangement of atoms and that during these processes atoms are not subdivided, created, or destroyed.

According to Gay Lussac's Law of Gaseous Volume, under same pressure and temperature, whenever gases react, they do so in volumes and volumes of reacting gases bear a simple ratio with each other and with product gases formed. 100 : 50 : 100 : : 2 : 1: 2 Hence, option B is correct.

Atomic no 24 is of Cr. Due to half filled orbital stability it doesnot follow Afbau rule so its configuration is 

Mass no. = no. of protons + no. of neutrons.

ψ has no physical significance while ψ2 represnts the probability density of finding an electron.

The bond order of given molecules are:
NO = 2.5, NO⁺ = 3, O₂ = 2, NO^– = 2
Larger the bond order, the smaller the bond length.
NO⁺ has the largest bond order 3.
Therefore, it will have the smallest bond length.
Hence option A is the answer.

The correct option is D.

• The proportion of covalent character in ionic bond is decided by polarisability of the metal cation as well as the electronegativity of both the elements involved in bonding.
• Polarisability is also decided by the density of +ve charge on the metal cation. 
• AlCl3 shows maximum covalent character. This is because Al cation has 3 unit +ve charge and shows strong tendency to distort the electron cloud

• The category "Genus" comprises a group of related species with more common characteristics than species of other genera.
• It is one level above species in the hierarchy.

The correct option is A Decrease
In the Linnaean system of hierarchy, as we go from species to kingdom, the number of common characters decreases, while in the descending order, the number of common characteristics increases. For example, any genus (lower grade of classification) has members with more similarities as compared to a family (a higher grade of classification) which has members with fewer similarities among them.

• Carl Linnaeus was a Swedish botanist, physician and zoologist, who laid the foundations for the modern biological naming scheme of biological nomenclature.
• He is known as the father of taxonomy and is also considered one of the fathers of modern ecology.
• In botany, the author abbreviation used to indicate Linnaeus as the authority for the species name. In older publications, sometimes the abbreviation "Linn" is found. Hence, L signifies the taxonomist, Linneaus.

Hence, the Correct Answer is C

• Unlike organisms in the other five kingdoms which are living, viruses are non-living organisms.
• They don’t even have basic unit of life i.e. cell.
• Hence, they are not categorised in any of the kingdoms.

Hence, the correct answer is B
NCERT Reference: Topic “Viroids” of chapter "Biological Classification" of NCERT.

Five kingdom classification was proposed by R.H. Whittaker in 1969.
The kingdoms identified by him were:

• Monera
• Protista
• Fungi
• Plantae  
• Animalia

Hence, the correct option is D
NCERT Reference: Topic- Five kingdom classification  of chapter "Biological Classification" of NCERT.

Heterotrophic bacteria are most abundant in nature. The majority are important decomposers.

Commonly known as sac-fungi, the ascomycetes are mostly multicellular, e.g., Penicillium, or rarely unicellular, e.g., yeast (Saccharomyces). They are saprophytic, decomposers, parasitic, or coprophilous (growing on dung).

Some members of deuteromycetes are saprophytes or parasites while a large number of them are decomposers of litter and help in mineral cycling. Some examples are Alternaria, Colletotrichum, and Trichoderma.

1. Pinus - Dioecious: Pinus species are actually monoecious, meaning that both male and female cones are present on the same tree. Therefore, this statement is a mismatch.

2. Cycas - Dioecious: Cycas, a type of cycads, is indeed dioecious, meaning male and female reproductive structures are on separate individuals. This statement is correct.

3. Salvinia - Heterosporous: Salvinia, a genus of aquatic ferns, is indeed heterosporous, meaning it produces two types of spores: microspores and megaspores. This statement is correct.

4. Equisetum - Homosporous: Equisetum, commonly known as horsetails, is indeed homosporous, producing only one type of spore that develops into a bisexual gametophyte. This statement is correct.

Thus, the mismatch is:

(1) Pinus - Dioecious

In Bryophytes, the sporophyte does not have a free-living stage. It is dependent on the gametophyte for nutrition and support. This contrasts with other plant groups like Pteridophytes and Gymnosperms, where the sporophyte is the dominant, free-living stage of the life cycle.

I. The stem is branched: This is generally true for many species of Pinus. Pines typically have branched stems, although the branching pattern can vary depending on the species and age of the tree.

II. Roots have fungal association in the form of mycorrhiza: This is also true. Pine trees form a mycorrhizal association with fungi. This symbiotic relationship is crucial for the tree's nutrient uptake, particularly in nutrient-poor soils.

III. The male and female strobili are borne on different trees: This statement is false. In Pinus, the male (pollen cones) and female (seed cones) strobili are typically borne on the same tree. Pines are monoecious, meaning they have both male and female reproductive structures on the same individual.

So, the correct statements about Pinus are I and II.

Asexual reproduction in liverworts takes place by fragmentation of thalli, or by the formation of specialised structures called gemmae (sing. gemma). Gemmae are green, multicellular, asexual buds, which develop in small receptacles called gemma cups located on the thalli. The gemmae become detached from the parent body and germinate to form new individuals.

• Pteridophytes are most primitive vascular flowerless, spore-producing cryptogamic land plants, commonly called vascular cryptogams.
• They are sometimes called as Amphibians/botanical snakes/spore producing seedless tracheophytes.
• They are the first vascular land plants to have an independent sporophyte diploid plant body with true root, stem and leaves.
• In contrast bryophytes, the amphibians of the plant kingdom are devoid of true roots, stem, and leaves, with no vascular supply but root-like, non-vascular rhizoids, leaf-like, and stem-like structures are present.

Hence, the correct option is C.
NCERT Reference: Topic “PTERIDOPHYTES” of chapter Plant Kingdom. 

• Symmetry is an attribute of an organism showing regularity in body parts on a plane or around an axis.
• In Phylum Echinodermata, the adult echinoderms are radially symmetrical but the larvae are bilaterally symmetrical. 

Hence, the correct option is B.

NCERT Reference: Topic: Phylum – Echinodermata” of chapter Animal Kingdom